1 /* 2 * Copyright (c) 2012 The DragonFly Project. All rights reserved. 3 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Matthew Dillon <dillon@backplane.com>, 7 * by Mihai Carabas <mihai.carabas@gmail.com> 8 * and many others. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 3. Neither the name of The DragonFly Project nor the names of its 21 * contributors may be used to endorse or promote products derived 22 * from this software without specific, prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 25 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 26 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 27 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 28 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 30 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 31 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 32 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 33 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 34 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 */ 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/kernel.h> 40 #include <sys/lock.h> 41 #include <sys/queue.h> 42 #include <sys/proc.h> 43 #include <sys/rtprio.h> 44 #include <sys/uio.h> 45 #include <sys/sysctl.h> 46 #include <sys/resourcevar.h> 47 #include <sys/spinlock.h> 48 #include <sys/cpu_topology.h> 49 #include <sys/thread2.h> 50 #include <sys/spinlock2.h> 51 #include <sys/mplock2.h> 52 53 #include <sys/ktr.h> 54 55 #include <machine/cpu.h> 56 #include <machine/smp.h> 57 58 /* 59 * Priorities. Note that with 32 run queues per scheduler each queue 60 * represents four priority levels. 61 */ 62 63 int dfly_rebalanced; 64 65 #define MAXPRI 128 66 #define PRIMASK (MAXPRI - 1) 67 #define PRIBASE_REALTIME 0 68 #define PRIBASE_NORMAL MAXPRI 69 #define PRIBASE_IDLE (MAXPRI * 2) 70 #define PRIBASE_THREAD (MAXPRI * 3) 71 #define PRIBASE_NULL (MAXPRI * 4) 72 73 #define NQS 32 /* 32 run queues. */ 74 #define PPQ (MAXPRI / NQS) /* priorities per queue */ 75 #define PPQMASK (PPQ - 1) 76 77 /* 78 * NICEPPQ - number of nice units per priority queue 79 * ESTCPUPPQ - number of estcpu units per priority queue 80 * ESTCPUMAX - number of estcpu units 81 */ 82 #define NICEPPQ 2 83 #define ESTCPUPPQ 512 84 #define ESTCPUMAX (ESTCPUPPQ * NQS) 85 #define BATCHMAX (ESTCPUFREQ * 30) 86 #define PRIO_RANGE (PRIO_MAX - PRIO_MIN + 1) 87 88 #define ESTCPULIM(v) min((v), ESTCPUMAX) 89 90 TAILQ_HEAD(rq, lwp); 91 92 #define lwp_priority lwp_usdata.dfly.priority 93 #define lwp_forked lwp_usdata.dfly.forked 94 #define lwp_rqindex lwp_usdata.dfly.rqindex 95 #define lwp_estcpu lwp_usdata.dfly.estcpu 96 #define lwp_estfast lwp_usdata.dfly.estfast 97 #define lwp_uload lwp_usdata.dfly.uload 98 #define lwp_rqtype lwp_usdata.dfly.rqtype 99 #define lwp_qcpu lwp_usdata.dfly.qcpu 100 #define lwp_rrcount lwp_usdata.dfly.rrcount 101 102 struct usched_dfly_pcpu { 103 struct spinlock spin; 104 struct thread helper_thread; 105 short unusde01; 106 short upri; 107 int uload; 108 int ucount; 109 struct lwp *uschedcp; 110 struct rq queues[NQS]; 111 struct rq rtqueues[NQS]; 112 struct rq idqueues[NQS]; 113 u_int32_t queuebits; 114 u_int32_t rtqueuebits; 115 u_int32_t idqueuebits; 116 int runqcount; 117 int cpuid; 118 cpumask_t cpumask; 119 #ifdef SMP 120 cpu_node_t *cpunode; 121 #endif 122 }; 123 124 typedef struct usched_dfly_pcpu *dfly_pcpu_t; 125 126 static void dfly_acquire_curproc(struct lwp *lp); 127 static void dfly_release_curproc(struct lwp *lp); 128 static void dfly_select_curproc(globaldata_t gd); 129 static void dfly_setrunqueue(struct lwp *lp); 130 static void dfly_setrunqueue_dd(dfly_pcpu_t rdd, struct lwp *lp); 131 static void dfly_schedulerclock(struct lwp *lp, sysclock_t period, 132 sysclock_t cpstamp); 133 static void dfly_recalculate_estcpu(struct lwp *lp); 134 static void dfly_resetpriority(struct lwp *lp); 135 static void dfly_forking(struct lwp *plp, struct lwp *lp); 136 static void dfly_exiting(struct lwp *lp, struct proc *); 137 static void dfly_uload_update(struct lwp *lp); 138 static void dfly_yield(struct lwp *lp); 139 #ifdef SMP 140 static void dfly_changeqcpu_locked(struct lwp *lp, 141 dfly_pcpu_t dd, dfly_pcpu_t rdd); 142 static dfly_pcpu_t dfly_choose_best_queue(struct lwp *lp); 143 static dfly_pcpu_t dfly_choose_worst_queue(dfly_pcpu_t dd); 144 static dfly_pcpu_t dfly_choose_queue_simple(dfly_pcpu_t dd, struct lwp *lp); 145 #endif 146 147 #ifdef SMP 148 static void dfly_need_user_resched_remote(void *dummy); 149 #endif 150 static struct lwp *dfly_chooseproc_locked(dfly_pcpu_t rdd, dfly_pcpu_t dd, 151 struct lwp *chklp, int worst); 152 static void dfly_remrunqueue_locked(dfly_pcpu_t dd, struct lwp *lp); 153 static void dfly_setrunqueue_locked(dfly_pcpu_t dd, struct lwp *lp); 154 155 struct usched usched_dfly = { 156 { NULL }, 157 "dfly", "Original DragonFly Scheduler", 158 NULL, /* default registration */ 159 NULL, /* default deregistration */ 160 dfly_acquire_curproc, 161 dfly_release_curproc, 162 dfly_setrunqueue, 163 dfly_schedulerclock, 164 dfly_recalculate_estcpu, 165 dfly_resetpriority, 166 dfly_forking, 167 dfly_exiting, 168 dfly_uload_update, 169 NULL, /* setcpumask not supported */ 170 dfly_yield 171 }; 172 173 /* 174 * We have NQS (32) run queues per scheduling class. For the normal 175 * class, there are 128 priorities scaled onto these 32 queues. New 176 * processes are added to the last entry in each queue, and processes 177 * are selected for running by taking them from the head and maintaining 178 * a simple FIFO arrangement. Realtime and Idle priority processes have 179 * and explicit 0-31 priority which maps directly onto their class queue 180 * index. When a queue has something in it, the corresponding bit is 181 * set in the queuebits variable, allowing a single read to determine 182 * the state of all 32 queues and then a ffs() to find the first busy 183 * queue. 184 */ 185 static cpumask_t dfly_curprocmask = -1; /* currently running a user process */ 186 static cpumask_t dfly_rdyprocmask; /* ready to accept a user process */ 187 #ifdef SMP 188 static volatile int dfly_scancpu; 189 #endif 190 static volatile int dfly_ucount; /* total running on whole system */ 191 static struct usched_dfly_pcpu dfly_pcpu[MAXCPU]; 192 static struct sysctl_ctx_list usched_dfly_sysctl_ctx; 193 static struct sysctl_oid *usched_dfly_sysctl_tree; 194 195 /* Debug info exposed through debug.* sysctl */ 196 197 static int usched_dfly_debug = -1; 198 SYSCTL_INT(_debug, OID_AUTO, dfly_scdebug, CTLFLAG_RW, 199 &usched_dfly_debug, 0, 200 "Print debug information for this pid"); 201 202 static int usched_dfly_pid_debug = -1; 203 SYSCTL_INT(_debug, OID_AUTO, dfly_pid_debug, CTLFLAG_RW, 204 &usched_dfly_pid_debug, 0, 205 "Print KTR debug information for this pid"); 206 207 static int usched_dfly_chooser = 0; 208 SYSCTL_INT(_debug, OID_AUTO, dfly_chooser, CTLFLAG_RW, 209 &usched_dfly_chooser, 0, 210 "Print KTR debug information for this pid"); 211 212 /* 213 * Tunning usched_dfly - configurable through kern.usched_dfly. 214 * 215 * weight1 - Tries to keep threads on their current cpu. If you 216 * make this value too large the scheduler will not be 217 * able to load-balance large loads. 218 * 219 * weight2 - If non-zero, detects thread pairs undergoing synchronous 220 * communications and tries to move them closer together. 221 * Behavior is adjusted by bit 4 of features (0x10). 222 * 223 * WARNING! Weight2 is a ridiculously sensitive parameter, 224 * a small value is recommended. 225 * 226 * weight3 - Weighting based on the number of recently runnable threads 227 * on the userland scheduling queue (ignoring their loads). 228 * A nominal value here prevents high-priority (low-load) 229 * threads from accumulating on one cpu core when other 230 * cores are available. 231 * 232 * This value should be left fairly small relative to weight1 233 * and weight4. 234 * 235 * weight4 - Weighting based on other cpu queues being available 236 * or running processes with higher lwp_priority's. 237 * 238 * This allows a thread to migrate to another nearby cpu if it 239 * is unable to run on the current cpu based on the other cpu 240 * being idle or running a lower priority (higher lwp_priority) 241 * thread. This value should be large enough to override weight1 242 * 243 * features - These flags can be set or cleared to enable or disable various 244 * features. 245 * 246 * 0x01 Enable idle-cpu pulling (default) 247 * 0x02 Enable proactive pushing (default) 248 * 0x04 Enable rebalancing rover (default) 249 * 0x08 Enable more proactive pushing (default) 250 * 0x10 (flip weight2 limit on same cpu) (default) 251 * 0x20 choose best cpu for forked process 252 * 0x40 choose current cpu for forked process 253 * 0x80 choose random cpu for forked process (default) 254 */ 255 #ifdef SMP 256 static int usched_dfly_smt = 0; 257 static int usched_dfly_cache_coherent = 0; 258 static int usched_dfly_weight1 = 200; /* keep thread on current cpu */ 259 static int usched_dfly_weight2 = 180; /* synchronous peer's current cpu */ 260 static int usched_dfly_weight3 = 40; /* number of threads on queue */ 261 static int usched_dfly_weight4 = 160; /* availability of idle cores */ 262 static int usched_dfly_fast_resched = 0;/* delta priority / resched */ 263 static int usched_dfly_features = 0x8F; /* allow pulls */ 264 static int usched_dfly_swmask = ~PPQMASK; /* allow pulls */ 265 #endif 266 static int usched_dfly_rrinterval = (ESTCPUFREQ + 9) / 10; 267 static int usched_dfly_decay = 8; 268 269 /* KTR debug printings */ 270 271 KTR_INFO_MASTER(usched); 272 273 #if !defined(KTR_USCHED_DFLY) 274 #define KTR_USCHED_DFLY KTR_ALL 275 #endif 276 277 KTR_INFO(KTR_USCHED_DFLY, usched, chooseproc, 0, 278 "USCHED_DFLY(chooseproc: pid %d, old_cpuid %d, curr_cpuid %d)", 279 pid_t pid, int old_cpuid, int curr); 280 281 /* 282 * This function is called when the kernel intends to return to userland. 283 * It is responsible for making the thread the current designated userland 284 * thread for this cpu, blocking if necessary. 285 * 286 * The kernel will not depress our LWKT priority until after we return, 287 * in case we have to shove over to another cpu. 288 * 289 * We must determine our thread's disposition before we switch away. This 290 * is very sensitive code. 291 * 292 * WARNING! THIS FUNCTION IS ALLOWED TO CAUSE THE CURRENT THREAD TO MIGRATE 293 * TO ANOTHER CPU! Because most of the kernel assumes that no migration will 294 * occur, this function is called only under very controlled circumstances. 295 */ 296 static void 297 dfly_acquire_curproc(struct lwp *lp) 298 { 299 globaldata_t gd; 300 dfly_pcpu_t dd; 301 #ifdef SMP 302 dfly_pcpu_t rdd; 303 #endif 304 thread_t td; 305 int force_resched; 306 307 /* 308 * Make sure we aren't sitting on a tsleep queue. 309 */ 310 td = lp->lwp_thread; 311 crit_enter_quick(td); 312 if (td->td_flags & TDF_TSLEEPQ) 313 tsleep_remove(td); 314 dfly_recalculate_estcpu(lp); 315 316 gd = mycpu; 317 dd = &dfly_pcpu[gd->gd_cpuid]; 318 319 /* 320 * Process any pending interrupts/ipi's, then handle reschedule 321 * requests. dfly_release_curproc() will try to assign a new 322 * uschedcp that isn't us and otherwise NULL it out. 323 */ 324 force_resched = 0; 325 if ((td->td_mpflags & TDF_MP_BATCH_DEMARC) && 326 lp->lwp_rrcount >= usched_dfly_rrinterval / 2) { 327 force_resched = 1; 328 } 329 330 if (user_resched_wanted()) { 331 if (dd->uschedcp == lp) 332 force_resched = 1; 333 clear_user_resched(); 334 dfly_release_curproc(lp); 335 } 336 337 /* 338 * Loop until we are the current user thread. 339 * 340 * NOTE: dd spinlock not held at top of loop. 341 */ 342 if (dd->uschedcp == lp) 343 lwkt_yield_quick(); 344 345 while (dd->uschedcp != lp) { 346 lwkt_yield_quick(); 347 348 spin_lock(&dd->spin); 349 350 /* 351 * We are not or are no longer the current lwp and a forced 352 * reschedule was requested. Figure out the best cpu to 353 * run on (our current cpu will be given significant weight). 354 * 355 * (if a reschedule was not requested we want to move this 356 * step after the uschedcp tests). 357 */ 358 #ifdef SMP 359 if (force_resched && 360 (usched_dfly_features & 0x08) && 361 (rdd = dfly_choose_best_queue(lp)) != dd) { 362 dfly_changeqcpu_locked(lp, dd, rdd); 363 spin_unlock(&dd->spin); 364 lwkt_deschedule(lp->lwp_thread); 365 dfly_setrunqueue_dd(rdd, lp); 366 lwkt_switch(); 367 gd = mycpu; 368 dd = &dfly_pcpu[gd->gd_cpuid]; 369 continue; 370 } 371 #endif 372 373 /* 374 * Either no reschedule was requested or the best queue was 375 * dd, and no current process has been selected. We can 376 * trivially become the current lwp on the current cpu. 377 */ 378 if (dd->uschedcp == NULL) { 379 atomic_set_cpumask(&dfly_curprocmask, gd->gd_cpumask); 380 dd->uschedcp = lp; 381 dd->upri = lp->lwp_priority; 382 KKASSERT(lp->lwp_qcpu == dd->cpuid); 383 spin_unlock(&dd->spin); 384 break; 385 } 386 387 /* 388 * Can we steal the current designated user thread? 389 * 390 * If we do the other thread will stall when it tries to 391 * return to userland, possibly rescheduling elsewhere. 392 * 393 * It is important to do a masked test to avoid the edge 394 * case where two near-equal-priority threads are constantly 395 * interrupting each other. 396 * 397 * In the exact match case another thread has already gained 398 * uschedcp and lowered its priority, if we steal it the 399 * other thread will stay stuck on the LWKT runq and not 400 * push to another cpu. So don't steal on equal-priority even 401 * though it might appear to be more beneficial due to not 402 * having to switch back to the other thread's context. 403 * 404 * usched_dfly_fast_resched requires that two threads be 405 * significantly far apart in priority in order to interrupt. 406 * 407 * If better but not sufficiently far apart, the current 408 * uschedcp will be interrupted at the next scheduler clock. 409 */ 410 if (dd->uschedcp && 411 (dd->upri & ~PPQMASK) > 412 (lp->lwp_priority & ~PPQMASK) + usched_dfly_fast_resched) { 413 dd->uschedcp = lp; 414 dd->upri = lp->lwp_priority; 415 KKASSERT(lp->lwp_qcpu == dd->cpuid); 416 spin_unlock(&dd->spin); 417 break; 418 } 419 #ifdef SMP 420 /* 421 * We are not the current lwp, figure out the best cpu 422 * to run on (our current cpu will be given significant 423 * weight). Loop on cpu change. 424 */ 425 if ((usched_dfly_features & 0x02) && 426 force_resched == 0 && 427 (rdd = dfly_choose_best_queue(lp)) != dd) { 428 dfly_changeqcpu_locked(lp, dd, rdd); 429 spin_unlock(&dd->spin); 430 lwkt_deschedule(lp->lwp_thread); 431 dfly_setrunqueue_dd(rdd, lp); 432 lwkt_switch(); 433 gd = mycpu; 434 dd = &dfly_pcpu[gd->gd_cpuid]; 435 continue; 436 } 437 #endif 438 439 /* 440 * We cannot become the current lwp, place the lp on the 441 * run-queue of this or another cpu and deschedule ourselves. 442 * 443 * When we are reactivated we will have another chance. 444 * 445 * Reload after a switch or setrunqueue/switch possibly 446 * moved us to another cpu. 447 */ 448 spin_unlock(&dd->spin); 449 lwkt_deschedule(lp->lwp_thread); 450 dfly_setrunqueue_dd(dd, lp); 451 lwkt_switch(); 452 gd = mycpu; 453 dd = &dfly_pcpu[gd->gd_cpuid]; 454 } 455 456 /* 457 * Make sure upri is synchronized, then yield to LWKT threads as 458 * needed before returning. This could result in another reschedule. 459 * XXX 460 */ 461 crit_exit_quick(td); 462 463 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0); 464 } 465 466 /* 467 * DFLY_RELEASE_CURPROC 468 * 469 * This routine detaches the current thread from the userland scheduler, 470 * usually because the thread needs to run or block in the kernel (at 471 * kernel priority) for a while. 472 * 473 * This routine is also responsible for selecting a new thread to 474 * make the current thread. 475 * 476 * NOTE: This implementation differs from the dummy example in that 477 * dfly_select_curproc() is able to select the current process, whereas 478 * dummy_select_curproc() is not able to select the current process. 479 * This means we have to NULL out uschedcp. 480 * 481 * Additionally, note that we may already be on a run queue if releasing 482 * via the lwkt_switch() in dfly_setrunqueue(). 483 */ 484 static void 485 dfly_release_curproc(struct lwp *lp) 486 { 487 globaldata_t gd = mycpu; 488 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid]; 489 490 /* 491 * Make sure td_wakefromcpu is defaulted. This will be overwritten 492 * by wakeup(). 493 */ 494 if (dd->uschedcp == lp) { 495 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0); 496 spin_lock(&dd->spin); 497 if (dd->uschedcp == lp) { 498 dd->uschedcp = NULL; /* don't let lp be selected */ 499 dd->upri = PRIBASE_NULL; 500 atomic_clear_cpumask(&dfly_curprocmask, gd->gd_cpumask); 501 spin_unlock(&dd->spin); 502 dfly_select_curproc(gd); 503 } else { 504 spin_unlock(&dd->spin); 505 } 506 } 507 } 508 509 /* 510 * DFLY_SELECT_CURPROC 511 * 512 * Select a new current process for this cpu and clear any pending user 513 * reschedule request. The cpu currently has no current process. 514 * 515 * This routine is also responsible for equal-priority round-robining, 516 * typically triggered from dfly_schedulerclock(). In our dummy example 517 * all the 'user' threads are LWKT scheduled all at once and we just 518 * call lwkt_switch(). 519 * 520 * The calling process is not on the queue and cannot be selected. 521 */ 522 static 523 void 524 dfly_select_curproc(globaldata_t gd) 525 { 526 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid]; 527 struct lwp *nlp; 528 int cpuid = gd->gd_cpuid; 529 530 crit_enter_gd(gd); 531 532 spin_lock(&dd->spin); 533 nlp = dfly_chooseproc_locked(dd, dd, dd->uschedcp, 0); 534 535 if (nlp) { 536 atomic_set_cpumask(&dfly_curprocmask, CPUMASK(cpuid)); 537 dd->upri = nlp->lwp_priority; 538 dd->uschedcp = nlp; 539 #if 0 540 dd->rrcount = 0; /* reset round robin */ 541 #endif 542 spin_unlock(&dd->spin); 543 #ifdef SMP 544 lwkt_acquire(nlp->lwp_thread); 545 #endif 546 lwkt_schedule(nlp->lwp_thread); 547 } else { 548 spin_unlock(&dd->spin); 549 } 550 crit_exit_gd(gd); 551 } 552 553 /* 554 * Place the specified lwp on the user scheduler's run queue. This routine 555 * must be called with the thread descheduled. The lwp must be runnable. 556 * It must not be possible for anyone else to explicitly schedule this thread. 557 * 558 * The thread may be the current thread as a special case. 559 */ 560 static void 561 dfly_setrunqueue(struct lwp *lp) 562 { 563 dfly_pcpu_t dd; 564 dfly_pcpu_t rdd; 565 566 /* 567 * First validate the process LWKT state. 568 */ 569 KASSERT(lp->lwp_stat == LSRUN, ("setrunqueue: lwp not LSRUN")); 570 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0, 571 ("lwp %d/%d already on runq! flag %08x/%08x", lp->lwp_proc->p_pid, 572 lp->lwp_tid, lp->lwp_proc->p_flags, lp->lwp_flags)); 573 KKASSERT((lp->lwp_thread->td_flags & TDF_RUNQ) == 0); 574 575 /* 576 * NOTE: dd/rdd do not necessarily represent the current cpu. 577 * Instead they may represent the cpu the thread was last 578 * scheduled on or inherited by its parent. 579 */ 580 dd = &dfly_pcpu[lp->lwp_qcpu]; 581 rdd = dd; 582 583 /* 584 * This process is not supposed to be scheduled anywhere or assigned 585 * as the current process anywhere. Assert the condition. 586 */ 587 KKASSERT(rdd->uschedcp != lp); 588 589 #ifndef SMP 590 /* 591 * If we are not SMP we do not have a scheduler helper to kick 592 * and must directly activate the process if none are scheduled. 593 * 594 * This is really only an issue when bootstrapping init since 595 * the caller in all other cases will be a user process, and 596 * even if released (rdd->uschedcp == NULL), that process will 597 * kickstart the scheduler when it returns to user mode from 598 * the kernel. 599 * 600 * NOTE: On SMP we can't just set some other cpu's uschedcp. 601 */ 602 if (rdd->uschedcp == NULL) { 603 spin_lock(&rdd->spin); 604 if (rdd->uschedcp == NULL) { 605 atomic_set_cpumask(&dfly_curprocmask, 1); 606 rdd->uschedcp = lp; 607 rdd->upri = lp->lwp_priority; 608 spin_unlock(&rdd->spin); 609 lwkt_schedule(lp->lwp_thread); 610 return; 611 } 612 spin_unlock(&rdd->spin); 613 } 614 #endif 615 616 #ifdef SMP 617 /* 618 * Ok, we have to setrunqueue some target cpu and request a reschedule 619 * if necessary. 620 * 621 * We have to choose the best target cpu. It might not be the current 622 * target even if the current cpu has no running user thread (for 623 * example, because the current cpu might be a hyperthread and its 624 * sibling has a thread assigned). 625 * 626 * If we just forked it is most optimal to run the child on the same 627 * cpu just in case the parent decides to wait for it (thus getting 628 * off that cpu). As long as there is nothing else runnable on the 629 * cpu, that is. If we did this unconditionally a parent forking 630 * multiple children before waiting (e.g. make -j N) leaves other 631 * cpus idle that could be working. 632 */ 633 if (lp->lwp_forked) { 634 lp->lwp_forked = 0; 635 if (usched_dfly_features & 0x20) 636 rdd = dfly_choose_best_queue(lp); 637 else if (usched_dfly_features & 0x40) 638 rdd = &dfly_pcpu[lp->lwp_qcpu]; 639 else if (usched_dfly_features & 0x80) 640 rdd = dfly_choose_queue_simple(rdd, lp); 641 else if (dfly_pcpu[lp->lwp_qcpu].runqcount) 642 rdd = dfly_choose_best_queue(lp); 643 else 644 rdd = &dfly_pcpu[lp->lwp_qcpu]; 645 } else { 646 rdd = dfly_choose_best_queue(lp); 647 /* rdd = &dfly_pcpu[lp->lwp_qcpu]; */ 648 } 649 if (lp->lwp_qcpu != rdd->cpuid) { 650 spin_lock(&dd->spin); 651 dfly_changeqcpu_locked(lp, dd, rdd); 652 spin_unlock(&dd->spin); 653 } 654 #endif 655 dfly_setrunqueue_dd(rdd, lp); 656 } 657 658 #ifdef SMP 659 660 /* 661 * Change qcpu to rdd->cpuid. The dd the lp is CURRENTLY on must be 662 * spin-locked on-call. rdd does not have to be. 663 */ 664 static void 665 dfly_changeqcpu_locked(struct lwp *lp, dfly_pcpu_t dd, dfly_pcpu_t rdd) 666 { 667 if (lp->lwp_qcpu != rdd->cpuid) { 668 if (lp->lwp_mpflags & LWP_MP_ULOAD) { 669 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ULOAD); 670 atomic_add_int(&dd->uload, -lp->lwp_uload); 671 atomic_add_int(&dd->ucount, -1); 672 atomic_add_int(&dfly_ucount, -1); 673 } 674 lp->lwp_qcpu = rdd->cpuid; 675 } 676 } 677 678 #endif 679 680 /* 681 * Place lp on rdd's runqueue. Nothing is locked on call. This function 682 * also performs all necessary ancillary notification actions. 683 */ 684 static void 685 dfly_setrunqueue_dd(dfly_pcpu_t rdd, struct lwp *lp) 686 { 687 #ifdef SMP 688 globaldata_t rgd; 689 690 /* 691 * We might be moving the lp to another cpu's run queue, and once 692 * on the runqueue (even if it is our cpu's), another cpu can rip 693 * it away from us. 694 * 695 * TDF_MIGRATING might already be set if this is part of a 696 * remrunqueue+setrunqueue sequence. 697 */ 698 if ((lp->lwp_thread->td_flags & TDF_MIGRATING) == 0) 699 lwkt_giveaway(lp->lwp_thread); 700 701 rgd = globaldata_find(rdd->cpuid); 702 703 /* 704 * We lose control of the lp the moment we release the spinlock 705 * after having placed it on the queue. i.e. another cpu could pick 706 * it up, or it could exit, or its priority could be further 707 * adjusted, or something like that. 708 * 709 * WARNING! rdd can point to a foreign cpu! 710 */ 711 spin_lock(&rdd->spin); 712 dfly_setrunqueue_locked(rdd, lp); 713 714 /* 715 * Potentially interrupt the currently-running thread 716 */ 717 if ((rdd->upri & ~PPQMASK) <= (lp->lwp_priority & ~PPQMASK)) { 718 /* 719 * Currently running thread is better or same, do not 720 * interrupt. 721 */ 722 spin_unlock(&rdd->spin); 723 } else if ((rdd->upri & ~PPQMASK) <= (lp->lwp_priority & ~PPQMASK) + 724 usched_dfly_fast_resched) { 725 /* 726 * Currently running thread is not better, but not so bad 727 * that we need to interrupt it. Let it run for one more 728 * scheduler tick. 729 */ 730 if (rdd->uschedcp && 731 rdd->uschedcp->lwp_rrcount < usched_dfly_rrinterval) { 732 rdd->uschedcp->lwp_rrcount = usched_dfly_rrinterval - 1; 733 } 734 spin_unlock(&rdd->spin); 735 } else if (rgd == mycpu) { 736 /* 737 * We should interrupt the currently running thread, which 738 * is on the current cpu. 739 */ 740 spin_unlock(&rdd->spin); 741 if (rdd->uschedcp == NULL) { 742 wakeup_mycpu(&rdd->helper_thread); /* XXX */ 743 need_user_resched(); 744 } else { 745 need_user_resched(); 746 } 747 } else { 748 /* 749 * We should interrupt the currently running thread, which 750 * is on a different cpu. 751 */ 752 spin_unlock(&rdd->spin); 753 lwkt_send_ipiq(rgd, dfly_need_user_resched_remote, NULL); 754 } 755 #else 756 /* 757 * Request a reschedule if appropriate. 758 */ 759 spin_lock(&rdd->spin); 760 dfly_setrunqueue_locked(rdd, lp); 761 spin_unlock(&rdd->spin); 762 if ((rdd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) { 763 need_user_resched(); 764 } 765 #endif 766 } 767 768 /* 769 * This routine is called from a systimer IPI. It MUST be MP-safe and 770 * the BGL IS NOT HELD ON ENTRY. This routine is called at ESTCPUFREQ on 771 * each cpu. 772 */ 773 static 774 void 775 dfly_schedulerclock(struct lwp *lp, sysclock_t period, sysclock_t cpstamp) 776 { 777 globaldata_t gd = mycpu; 778 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid]; 779 780 /* 781 * Spinlocks also hold a critical section so there should not be 782 * any active. 783 */ 784 KKASSERT(gd->gd_spinlocks == 0); 785 786 if (lp == NULL) 787 return; 788 789 /* 790 * Do we need to round-robin? We round-robin 10 times a second. 791 * This should only occur for cpu-bound batch processes. 792 */ 793 if (++lp->lwp_rrcount >= usched_dfly_rrinterval) { 794 lp->lwp_thread->td_wakefromcpu = -1; 795 need_user_resched(); 796 } 797 798 /* 799 * Adjust estcpu upward using a real time equivalent calculation, 800 * and recalculate lp's priority. 801 */ 802 lp->lwp_estcpu = ESTCPULIM(lp->lwp_estcpu + ESTCPUMAX / ESTCPUFREQ + 1); 803 dfly_resetpriority(lp); 804 805 /* 806 * Rebalance two cpus every 8 ticks, pulling the worst thread 807 * from the worst cpu's queue into a rotating cpu number. 808 * 809 * This mechanic is needed because the push algorithms can 810 * steady-state in an non-optimal configuration. We need to mix it 811 * up a little, even if it means breaking up a paired thread, so 812 * the push algorithms can rebalance the degenerate conditions. 813 * This portion of the algorithm exists to ensure stability at the 814 * selected weightings. 815 * 816 * Because we might be breaking up optimal conditions we do not want 817 * to execute this too quickly, hence we only rebalance approximately 818 * ~7-8 times per second. The push's, on the otherhand, are capable 819 * moving threads to other cpus at a much higher rate. 820 * 821 * We choose the most heavily loaded thread from the worst queue 822 * in order to ensure that multiple heavy-weight threads on the same 823 * queue get broken up, and also because these threads are the most 824 * likely to be able to remain in place. Hopefully then any pairings, 825 * if applicable, migrate to where these threads are. 826 */ 827 #ifdef SMP 828 if ((usched_dfly_features & 0x04) && 829 ((u_int)sched_ticks & 7) == 0 && 830 (u_int)sched_ticks / 8 % ncpus == gd->gd_cpuid) { 831 /* 832 * Our cpu is up. 833 */ 834 struct lwp *nlp; 835 dfly_pcpu_t rdd; 836 837 rdd = dfly_choose_worst_queue(dd); 838 if (rdd) { 839 spin_lock(&dd->spin); 840 if (spin_trylock(&rdd->spin)) { 841 nlp = dfly_chooseproc_locked(rdd, dd, NULL, 1); 842 spin_unlock(&rdd->spin); 843 if (nlp == NULL) 844 spin_unlock(&dd->spin); 845 } else { 846 spin_unlock(&dd->spin); 847 nlp = NULL; 848 } 849 } else { 850 nlp = NULL; 851 } 852 /* dd->spin held if nlp != NULL */ 853 854 /* 855 * Either schedule it or add it to our queue. 856 */ 857 if (nlp && 858 (nlp->lwp_priority & ~PPQMASK) < (dd->upri & ~PPQMASK)) { 859 atomic_set_cpumask(&dfly_curprocmask, dd->cpumask); 860 dd->upri = nlp->lwp_priority; 861 dd->uschedcp = nlp; 862 #if 0 863 dd->rrcount = 0; /* reset round robin */ 864 #endif 865 spin_unlock(&dd->spin); 866 lwkt_acquire(nlp->lwp_thread); 867 lwkt_schedule(nlp->lwp_thread); 868 } else if (nlp) { 869 dfly_setrunqueue_locked(dd, nlp); 870 spin_unlock(&dd->spin); 871 } 872 } 873 #endif 874 } 875 876 /* 877 * Called from acquire and from kern_synch's one-second timer (one of the 878 * callout helper threads) with a critical section held. 879 * 880 * Adjust p_estcpu based on our single-cpu load, p_nice, and compensate for 881 * overall system load. 882 * 883 * Note that no recalculation occurs for a process which sleeps and wakes 884 * up in the same tick. That is, a system doing thousands of context 885 * switches per second will still only do serious estcpu calculations 886 * ESTCPUFREQ times per second. 887 */ 888 static 889 void 890 dfly_recalculate_estcpu(struct lwp *lp) 891 { 892 globaldata_t gd = mycpu; 893 sysclock_t cpbase; 894 sysclock_t ttlticks; 895 int estcpu; 896 int decay_factor; 897 int ucount; 898 899 /* 900 * We have to subtract periodic to get the last schedclock 901 * timeout time, otherwise we would get the upcoming timeout. 902 * Keep in mind that a process can migrate between cpus and 903 * while the scheduler clock should be very close, boundary 904 * conditions could lead to a small negative delta. 905 */ 906 cpbase = gd->gd_schedclock.time - gd->gd_schedclock.periodic; 907 908 if (lp->lwp_slptime > 1) { 909 /* 910 * Too much time has passed, do a coarse correction. 911 */ 912 lp->lwp_estcpu = lp->lwp_estcpu >> 1; 913 dfly_resetpriority(lp); 914 lp->lwp_cpbase = cpbase; 915 lp->lwp_cpticks = 0; 916 lp->lwp_estfast = 0; 917 } else if (lp->lwp_cpbase != cpbase) { 918 /* 919 * Adjust estcpu if we are in a different tick. Don't waste 920 * time if we are in the same tick. 921 * 922 * First calculate the number of ticks in the measurement 923 * interval. The ttlticks calculation can wind up 0 due to 924 * a bug in the handling of lwp_slptime (as yet not found), 925 * so make sure we do not get a divide by 0 panic. 926 */ 927 ttlticks = (cpbase - lp->lwp_cpbase) / 928 gd->gd_schedclock.periodic; 929 if (ttlticks < 0) { 930 ttlticks = 0; 931 lp->lwp_cpbase = cpbase; 932 } 933 if (ttlticks == 0) 934 return; 935 updatepcpu(lp, lp->lwp_cpticks, ttlticks); 936 937 /* 938 * Calculate the percentage of one cpu being used then 939 * compensate for any system load in excess of ncpus. 940 * 941 * For example, if we have 8 cores and 16 running cpu-bound 942 * processes then all things being equal each process will 943 * get 50% of one cpu. We need to pump this value back 944 * up to 100% so the estcpu calculation properly adjusts 945 * the process's dynamic priority. 946 * 947 * estcpu is scaled by ESTCPUMAX, pctcpu is scaled by FSCALE. 948 */ 949 estcpu = (lp->lwp_pctcpu * ESTCPUMAX) >> FSHIFT; 950 ucount = dfly_ucount; 951 if (ucount > ncpus) { 952 estcpu += estcpu * (ucount - ncpus) / ncpus; 953 } 954 955 if (usched_dfly_debug == lp->lwp_proc->p_pid) { 956 kprintf("pid %d lwp %p estcpu %3d %3d cp %d/%d", 957 lp->lwp_proc->p_pid, lp, 958 estcpu, lp->lwp_estcpu, 959 lp->lwp_cpticks, ttlticks); 960 } 961 962 /* 963 * Adjust lp->lwp_esetcpu. The decay factor determines how 964 * quickly lwp_estcpu collapses to its realtime calculation. 965 * A slower collapse gives us a more accurate number over 966 * the long term but can create problems with bursty threads 967 * or threads which become cpu hogs. 968 * 969 * To solve this problem, newly started lwps and lwps which 970 * are restarting after having been asleep for a while are 971 * given a much, much faster decay in order to quickly 972 * detect whether they become cpu-bound. 973 * 974 * NOTE: p_nice is accounted for in dfly_resetpriority(), 975 * and not here, but we must still ensure that a 976 * cpu-bound nice -20 process does not completely 977 * override a cpu-bound nice +20 process. 978 * 979 * NOTE: We must use ESTCPULIM() here to deal with any 980 * overshoot. 981 */ 982 decay_factor = usched_dfly_decay; 983 if (decay_factor < 1) 984 decay_factor = 1; 985 if (decay_factor > 1024) 986 decay_factor = 1024; 987 988 if (lp->lwp_estfast < usched_dfly_decay) { 989 ++lp->lwp_estfast; 990 lp->lwp_estcpu = ESTCPULIM( 991 (lp->lwp_estcpu * lp->lwp_estfast + estcpu) / 992 (lp->lwp_estfast + 1)); 993 } else { 994 lp->lwp_estcpu = ESTCPULIM( 995 (lp->lwp_estcpu * decay_factor + estcpu) / 996 (decay_factor + 1)); 997 } 998 999 if (usched_dfly_debug == lp->lwp_proc->p_pid) 1000 kprintf(" finalestcpu %d\n", lp->lwp_estcpu); 1001 dfly_resetpriority(lp); 1002 lp->lwp_cpbase += ttlticks * gd->gd_schedclock.periodic; 1003 lp->lwp_cpticks = 0; 1004 } 1005 } 1006 1007 /* 1008 * Compute the priority of a process when running in user mode. 1009 * Arrange to reschedule if the resulting priority is better 1010 * than that of the current process. 1011 * 1012 * This routine may be called with any process. 1013 * 1014 * This routine is called by fork1() for initial setup with the process 1015 * of the run queue, and also may be called normally with the process on or 1016 * off the run queue. 1017 */ 1018 static void 1019 dfly_resetpriority(struct lwp *lp) 1020 { 1021 dfly_pcpu_t rdd; 1022 int newpriority; 1023 u_short newrqtype; 1024 int rcpu; 1025 int checkpri; 1026 int estcpu; 1027 int delta_uload; 1028 1029 crit_enter(); 1030 1031 /* 1032 * Lock the scheduler (lp) belongs to. This can be on a different 1033 * cpu. Handle races. This loop breaks out with the appropriate 1034 * rdd locked. 1035 */ 1036 for (;;) { 1037 rcpu = lp->lwp_qcpu; 1038 cpu_ccfence(); 1039 rdd = &dfly_pcpu[rcpu]; 1040 spin_lock(&rdd->spin); 1041 if (rcpu == lp->lwp_qcpu) 1042 break; 1043 spin_unlock(&rdd->spin); 1044 } 1045 1046 /* 1047 * Calculate the new priority and queue type 1048 */ 1049 newrqtype = lp->lwp_rtprio.type; 1050 1051 switch(newrqtype) { 1052 case RTP_PRIO_REALTIME: 1053 case RTP_PRIO_FIFO: 1054 newpriority = PRIBASE_REALTIME + 1055 (lp->lwp_rtprio.prio & PRIMASK); 1056 break; 1057 case RTP_PRIO_NORMAL: 1058 /* 1059 * 1060 */ 1061 estcpu = lp->lwp_estcpu; 1062 1063 /* 1064 * p_nice piece Adds (0-40) * 2 0-80 1065 * estcpu Adds 16384 * 4 / 512 0-128 1066 */ 1067 newpriority = (lp->lwp_proc->p_nice - PRIO_MIN) * PPQ / NICEPPQ; 1068 newpriority += estcpu * PPQ / ESTCPUPPQ; 1069 newpriority = newpriority * MAXPRI / (PRIO_RANGE * PPQ / 1070 NICEPPQ + ESTCPUMAX * PPQ / ESTCPUPPQ); 1071 newpriority = PRIBASE_NORMAL + (newpriority & PRIMASK); 1072 break; 1073 case RTP_PRIO_IDLE: 1074 newpriority = PRIBASE_IDLE + (lp->lwp_rtprio.prio & PRIMASK); 1075 break; 1076 case RTP_PRIO_THREAD: 1077 newpriority = PRIBASE_THREAD + (lp->lwp_rtprio.prio & PRIMASK); 1078 break; 1079 default: 1080 panic("Bad RTP_PRIO %d", newrqtype); 1081 /* NOT REACHED */ 1082 } 1083 1084 /* 1085 * The LWKT scheduler doesn't dive usched structures, give it a hint 1086 * on the relative priority of user threads running in the kernel. 1087 * The LWKT scheduler will always ensure that a user thread running 1088 * in the kernel will get cpu some time, regardless of its upri, 1089 * but can decide not to instantly switch from one kernel or user 1090 * mode user thread to a kernel-mode user thread when it has a less 1091 * desireable user priority. 1092 * 1093 * td_upri has normal sense (higher values are more desireable), so 1094 * negate it. 1095 */ 1096 lp->lwp_thread->td_upri = -(newpriority & usched_dfly_swmask); 1097 1098 /* 1099 * The newpriority incorporates the queue type so do a simple masked 1100 * check to determine if the process has moved to another queue. If 1101 * it has, and it is currently on a run queue, then move it. 1102 * 1103 * Since uload is ~PPQMASK masked, no modifications are necessary if 1104 * we end up in the same run queue. 1105 */ 1106 if ((lp->lwp_priority ^ newpriority) & ~PPQMASK) { 1107 if (lp->lwp_mpflags & LWP_MP_ONRUNQ) { 1108 dfly_remrunqueue_locked(rdd, lp); 1109 lp->lwp_priority = newpriority; 1110 lp->lwp_rqtype = newrqtype; 1111 lp->lwp_rqindex = (newpriority & PRIMASK) / PPQ; 1112 dfly_setrunqueue_locked(rdd, lp); 1113 checkpri = 1; 1114 } else { 1115 lp->lwp_priority = newpriority; 1116 lp->lwp_rqtype = newrqtype; 1117 lp->lwp_rqindex = (newpriority & PRIMASK) / PPQ; 1118 checkpri = 0; 1119 } 1120 } else { 1121 /* 1122 * In the same PPQ, uload cannot change. 1123 */ 1124 lp->lwp_priority = newpriority; 1125 checkpri = 1; 1126 rcpu = -1; 1127 } 1128 1129 /* 1130 * Adjust effective load. 1131 * 1132 * Calculate load then scale up or down geometrically based on p_nice. 1133 * Processes niced up (positive) are less important, and processes 1134 * niced downard (negative) are more important. The higher the uload, 1135 * the more important the thread. 1136 */ 1137 /* 0-511, 0-100% cpu */ 1138 delta_uload = lp->lwp_estcpu / NQS; 1139 delta_uload -= delta_uload * lp->lwp_proc->p_nice / (PRIO_MAX + 1); 1140 1141 1142 delta_uload -= lp->lwp_uload; 1143 lp->lwp_uload += delta_uload; 1144 if (lp->lwp_mpflags & LWP_MP_ULOAD) 1145 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].uload, delta_uload); 1146 1147 /* 1148 * Determine if we need to reschedule the target cpu. This only 1149 * occurs if the LWP is already on a scheduler queue, which means 1150 * that idle cpu notification has already occured. At most we 1151 * need only issue a need_user_resched() on the appropriate cpu. 1152 * 1153 * The LWP may be owned by a CPU different from the current one, 1154 * in which case dd->uschedcp may be modified without an MP lock 1155 * or a spinlock held. The worst that happens is that the code 1156 * below causes a spurious need_user_resched() on the target CPU 1157 * and dd->pri to be wrong for a short period of time, both of 1158 * which are harmless. 1159 * 1160 * If checkpri is 0 we are adjusting the priority of the current 1161 * process, possibly higher (less desireable), so ignore the upri 1162 * check which will fail in that case. 1163 */ 1164 if (rcpu >= 0) { 1165 if ((dfly_rdyprocmask & CPUMASK(rcpu)) && 1166 (checkpri == 0 || 1167 (rdd->upri & ~PRIMASK) > 1168 (lp->lwp_priority & ~PRIMASK))) { 1169 #ifdef SMP 1170 if (rcpu == mycpu->gd_cpuid) { 1171 spin_unlock(&rdd->spin); 1172 need_user_resched(); 1173 } else { 1174 spin_unlock(&rdd->spin); 1175 lwkt_send_ipiq(globaldata_find(rcpu), 1176 dfly_need_user_resched_remote, 1177 NULL); 1178 } 1179 #else 1180 spin_unlock(&rdd->spin); 1181 need_user_resched(); 1182 #endif 1183 } else { 1184 spin_unlock(&rdd->spin); 1185 } 1186 } else { 1187 spin_unlock(&rdd->spin); 1188 } 1189 crit_exit(); 1190 } 1191 1192 static 1193 void 1194 dfly_yield(struct lwp *lp) 1195 { 1196 #if 0 1197 /* FUTURE (or something similar) */ 1198 switch(lp->lwp_rqtype) { 1199 case RTP_PRIO_NORMAL: 1200 lp->lwp_estcpu = ESTCPULIM(lp->lwp_estcpu + ESTCPUINCR); 1201 break; 1202 default: 1203 break; 1204 } 1205 #endif 1206 need_user_resched(); 1207 } 1208 1209 /* 1210 * Called from fork1() when a new child process is being created. 1211 * 1212 * Give the child process an initial estcpu that is more batch then 1213 * its parent and dock the parent for the fork (but do not 1214 * reschedule the parent). 1215 * 1216 * fast 1217 * 1218 * XXX lwp should be "spawning" instead of "forking" 1219 */ 1220 static void 1221 dfly_forking(struct lwp *plp, struct lwp *lp) 1222 { 1223 /* 1224 * Put the child 4 queue slots (out of 32) higher than the parent 1225 * (less desireable than the parent). 1226 */ 1227 lp->lwp_estcpu = ESTCPULIM(plp->lwp_estcpu + ESTCPUPPQ * 4); 1228 lp->lwp_forked = 1; 1229 lp->lwp_estfast = 0; 1230 1231 /* 1232 * Dock the parent a cost for the fork, protecting us from fork 1233 * bombs. If the parent is forking quickly make the child more 1234 * batchy. 1235 */ 1236 plp->lwp_estcpu = ESTCPULIM(plp->lwp_estcpu + ESTCPUPPQ / 16); 1237 } 1238 1239 /* 1240 * Called when a lwp is being removed from this scheduler, typically 1241 * during lwp_exit(). We have to clean out any ULOAD accounting before 1242 * we can let the lp go. The dd->spin lock is not needed for uload 1243 * updates. 1244 * 1245 * Scheduler dequeueing has already occurred, no further action in that 1246 * regard is needed. 1247 */ 1248 static void 1249 dfly_exiting(struct lwp *lp, struct proc *child_proc) 1250 { 1251 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu]; 1252 1253 if (lp->lwp_mpflags & LWP_MP_ULOAD) { 1254 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ULOAD); 1255 atomic_add_int(&dd->uload, -lp->lwp_uload); 1256 atomic_add_int(&dd->ucount, -1); 1257 atomic_add_int(&dfly_ucount, -1); 1258 } 1259 } 1260 1261 /* 1262 * This function cannot block in any way, but spinlocks are ok. 1263 * 1264 * Update the uload based on the state of the thread (whether it is going 1265 * to sleep or running again). The uload is meant to be a longer-term 1266 * load and not an instantanious load. 1267 */ 1268 static void 1269 dfly_uload_update(struct lwp *lp) 1270 { 1271 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu]; 1272 1273 if (lp->lwp_thread->td_flags & TDF_RUNQ) { 1274 if ((lp->lwp_mpflags & LWP_MP_ULOAD) == 0) { 1275 spin_lock(&dd->spin); 1276 if ((lp->lwp_mpflags & LWP_MP_ULOAD) == 0) { 1277 atomic_set_int(&lp->lwp_mpflags, 1278 LWP_MP_ULOAD); 1279 atomic_add_int(&dd->uload, lp->lwp_uload); 1280 atomic_add_int(&dd->ucount, 1); 1281 atomic_add_int(&dfly_ucount, 1); 1282 } 1283 spin_unlock(&dd->spin); 1284 } 1285 } else if (lp->lwp_slptime > 0) { 1286 if (lp->lwp_mpflags & LWP_MP_ULOAD) { 1287 spin_lock(&dd->spin); 1288 if (lp->lwp_mpflags & LWP_MP_ULOAD) { 1289 atomic_clear_int(&lp->lwp_mpflags, 1290 LWP_MP_ULOAD); 1291 atomic_add_int(&dd->uload, -lp->lwp_uload); 1292 atomic_add_int(&dd->ucount, -1); 1293 atomic_add_int(&dfly_ucount, -1); 1294 } 1295 spin_unlock(&dd->spin); 1296 } 1297 } 1298 } 1299 1300 /* 1301 * chooseproc() is called when a cpu needs a user process to LWKT schedule, 1302 * it selects a user process and returns it. If chklp is non-NULL and chklp 1303 * has a better or equal priority then the process that would otherwise be 1304 * chosen, NULL is returned. 1305 * 1306 * Until we fix the RUNQ code the chklp test has to be strict or we may 1307 * bounce between processes trying to acquire the current process designation. 1308 * 1309 * Must be called with rdd->spin locked. The spinlock is left intact through 1310 * the entire routine. dd->spin does not have to be locked. 1311 * 1312 * If worst is non-zero this function finds the worst thread instead of the 1313 * best thread (used by the schedulerclock-based rover). 1314 */ 1315 static 1316 struct lwp * 1317 dfly_chooseproc_locked(dfly_pcpu_t rdd, dfly_pcpu_t dd, 1318 struct lwp *chklp, int worst) 1319 { 1320 struct lwp *lp; 1321 struct rq *q; 1322 u_int32_t *which, *which2; 1323 u_int32_t pri; 1324 u_int32_t rtqbits; 1325 u_int32_t tsqbits; 1326 u_int32_t idqbits; 1327 1328 rtqbits = rdd->rtqueuebits; 1329 tsqbits = rdd->queuebits; 1330 idqbits = rdd->idqueuebits; 1331 1332 if (worst) { 1333 if (idqbits) { 1334 pri = bsrl(idqbits); 1335 q = &rdd->idqueues[pri]; 1336 which = &rdd->idqueuebits; 1337 which2 = &idqbits; 1338 } else if (tsqbits) { 1339 pri = bsrl(tsqbits); 1340 q = &rdd->queues[pri]; 1341 which = &rdd->queuebits; 1342 which2 = &tsqbits; 1343 } else if (rtqbits) { 1344 pri = bsrl(rtqbits); 1345 q = &rdd->rtqueues[pri]; 1346 which = &rdd->rtqueuebits; 1347 which2 = &rtqbits; 1348 } else { 1349 return (NULL); 1350 } 1351 lp = TAILQ_LAST(q, rq); 1352 } else { 1353 if (rtqbits) { 1354 pri = bsfl(rtqbits); 1355 q = &rdd->rtqueues[pri]; 1356 which = &rdd->rtqueuebits; 1357 which2 = &rtqbits; 1358 } else if (tsqbits) { 1359 pri = bsfl(tsqbits); 1360 q = &rdd->queues[pri]; 1361 which = &rdd->queuebits; 1362 which2 = &tsqbits; 1363 } else if (idqbits) { 1364 pri = bsfl(idqbits); 1365 q = &rdd->idqueues[pri]; 1366 which = &rdd->idqueuebits; 1367 which2 = &idqbits; 1368 } else { 1369 return (NULL); 1370 } 1371 lp = TAILQ_FIRST(q); 1372 } 1373 KASSERT(lp, ("chooseproc: no lwp on busy queue")); 1374 1375 /* 1376 * If the passed lwp <chklp> is reasonably close to the selected 1377 * lwp <lp>, return NULL (indicating that <chklp> should be kept). 1378 * 1379 * Note that we must error on the side of <chklp> to avoid bouncing 1380 * between threads in the acquire code. 1381 */ 1382 if (chklp) { 1383 if (chklp->lwp_priority < lp->lwp_priority + PPQ) 1384 return(NULL); 1385 } 1386 1387 KTR_COND_LOG(usched_chooseproc, 1388 lp->lwp_proc->p_pid == usched_dfly_pid_debug, 1389 lp->lwp_proc->p_pid, 1390 lp->lwp_thread->td_gd->gd_cpuid, 1391 mycpu->gd_cpuid); 1392 1393 KASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) != 0, ("not on runq6!")); 1394 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ); 1395 TAILQ_REMOVE(q, lp, lwp_procq); 1396 --rdd->runqcount; 1397 if (TAILQ_EMPTY(q)) 1398 *which &= ~(1 << pri); 1399 1400 /* 1401 * If we are choosing a process from rdd with the intent to 1402 * move it to dd, lwp_qcpu must be adjusted while rdd's spinlock 1403 * is still held. 1404 */ 1405 if (rdd != dd) { 1406 if (lp->lwp_mpflags & LWP_MP_ULOAD) { 1407 atomic_add_int(&rdd->uload, -lp->lwp_uload); 1408 atomic_add_int(&rdd->ucount, -1); 1409 atomic_add_int(&dfly_ucount, -1); 1410 } 1411 lp->lwp_qcpu = dd->cpuid; 1412 atomic_add_int(&dd->uload, lp->lwp_uload); 1413 atomic_add_int(&dd->ucount, 1); 1414 atomic_add_int(&dfly_ucount, 1); 1415 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ULOAD); 1416 } 1417 return lp; 1418 } 1419 1420 #ifdef SMP 1421 1422 /* 1423 * USED TO PUSH RUNNABLE LWPS TO THE LEAST LOADED CPU. 1424 * 1425 * Choose a cpu node to schedule lp on, hopefully nearby its current 1426 * node. 1427 * 1428 * We give the current node a modest advantage for obvious reasons. 1429 * 1430 * We also give the node the thread was woken up FROM a slight advantage 1431 * in order to try to schedule paired threads which synchronize/block waiting 1432 * for each other fairly close to each other. Similarly in a network setting 1433 * this feature will also attempt to place a user process near the kernel 1434 * protocol thread that is feeding it data. THIS IS A CRITICAL PART of the 1435 * algorithm as it heuristically groups synchronizing processes for locality 1436 * of reference in multi-socket systems. 1437 * 1438 * We check against running processes and give a big advantage if there 1439 * are none running. 1440 * 1441 * The caller will normally dfly_setrunqueue() lp on the returned queue. 1442 * 1443 * When the topology is known choose a cpu whos group has, in aggregate, 1444 * has the lowest weighted load. 1445 */ 1446 static 1447 dfly_pcpu_t 1448 dfly_choose_best_queue(struct lwp *lp) 1449 { 1450 cpumask_t wakemask; 1451 cpumask_t mask; 1452 cpu_node_t *cpup; 1453 cpu_node_t *cpun; 1454 cpu_node_t *cpub; 1455 dfly_pcpu_t dd = &dfly_pcpu[lp->lwp_qcpu]; 1456 dfly_pcpu_t rdd; 1457 int wakecpu; 1458 int cpuid; 1459 int n; 1460 int count; 1461 int load; 1462 int lowest_load; 1463 1464 /* 1465 * When the topology is unknown choose a random cpu that is hopefully 1466 * idle. 1467 */ 1468 if (dd->cpunode == NULL) 1469 return (dfly_choose_queue_simple(dd, lp)); 1470 1471 /* 1472 * Pairing mask 1473 */ 1474 if ((wakecpu = lp->lwp_thread->td_wakefromcpu) >= 0) 1475 wakemask = dfly_pcpu[wakecpu].cpumask; 1476 else 1477 wakemask = 0; 1478 1479 /* 1480 * When the topology is known choose a cpu whos group has, in 1481 * aggregate, has the lowest weighted load. 1482 */ 1483 cpup = root_cpu_node; 1484 rdd = dd; 1485 1486 while (cpup) { 1487 /* 1488 * Degenerate case super-root 1489 */ 1490 if (cpup->child_node && cpup->child_no == 1) { 1491 cpup = cpup->child_node; 1492 continue; 1493 } 1494 1495 /* 1496 * Terminal cpunode 1497 */ 1498 if (cpup->child_node == NULL) { 1499 rdd = &dfly_pcpu[BSFCPUMASK(cpup->members)]; 1500 break; 1501 } 1502 1503 cpub = NULL; 1504 lowest_load = 0x7FFFFFFF; 1505 1506 for (n = 0; n < cpup->child_no; ++n) { 1507 /* 1508 * Accumulate load information for all cpus 1509 * which are members of this node. 1510 */ 1511 cpun = &cpup->child_node[n]; 1512 mask = cpun->members & usched_global_cpumask & 1513 smp_active_mask & lp->lwp_cpumask; 1514 if (mask == 0) 1515 continue; 1516 1517 count = 0; 1518 load = 0; 1519 1520 while (mask) { 1521 cpuid = BSFCPUMASK(mask); 1522 rdd = &dfly_pcpu[cpuid]; 1523 load += rdd->uload; 1524 load += rdd->ucount * usched_dfly_weight3; 1525 1526 if (rdd->uschedcp == NULL && 1527 rdd->runqcount == 0 && 1528 globaldata_find(cpuid)->gd_tdrunqcount == 0 1529 ) { 1530 load -= usched_dfly_weight4; 1531 } 1532 #if 0 1533 else if (rdd->upri > lp->lwp_priority + PPQ) { 1534 load -= usched_dfly_weight4 / 2; 1535 } 1536 #endif 1537 mask &= ~CPUMASK(cpuid); 1538 ++count; 1539 } 1540 1541 /* 1542 * Compensate if the lp is already accounted for in 1543 * the aggregate uload for this mask set. We want 1544 * to calculate the loads as if lp were not present, 1545 * otherwise the calculation is bogus. 1546 */ 1547 if ((lp->lwp_mpflags & LWP_MP_ULOAD) && 1548 (dd->cpumask & cpun->members)) { 1549 load -= lp->lwp_uload; 1550 load -= usched_dfly_weight3; 1551 } 1552 1553 load /= count; 1554 1555 /* 1556 * Advantage the cpu group (lp) is already on. 1557 */ 1558 if (cpun->members & dd->cpumask) 1559 load -= usched_dfly_weight1; 1560 1561 /* 1562 * Advantage the cpu group we want to pair (lp) to, 1563 * but don't let it go to the exact same cpu as 1564 * the wakecpu target. 1565 * 1566 * We do this by checking whether cpun is a 1567 * terminal node or not. All cpun's at the same 1568 * level will either all be terminal or all not 1569 * terminal. 1570 * 1571 * If it is and we match we disadvantage the load. 1572 * If it is and we don't match we advantage the load. 1573 * 1574 * Also note that we are effectively disadvantaging 1575 * all-but-one by the same amount, so it won't effect 1576 * the weight1 factor for the all-but-one nodes. 1577 */ 1578 if (cpun->members & wakemask) { 1579 if (cpun->child_node != NULL) { 1580 /* advantage */ 1581 load -= usched_dfly_weight2; 1582 } else { 1583 if (usched_dfly_features & 0x10) 1584 load += usched_dfly_weight2; 1585 else 1586 load -= usched_dfly_weight2; 1587 } 1588 } 1589 1590 /* 1591 * Calculate the best load 1592 */ 1593 if (cpub == NULL || lowest_load > load || 1594 (lowest_load == load && 1595 (cpun->members & dd->cpumask)) 1596 ) { 1597 lowest_load = load; 1598 cpub = cpun; 1599 } 1600 } 1601 cpup = cpub; 1602 } 1603 if (usched_dfly_chooser) 1604 kprintf("lp %02d->%02d %s\n", 1605 lp->lwp_qcpu, rdd->cpuid, lp->lwp_proc->p_comm); 1606 return (rdd); 1607 } 1608 1609 /* 1610 * USED TO PULL RUNNABLE LWPS FROM THE MOST LOADED CPU. 1611 * 1612 * Choose the worst queue close to dd's cpu node with a non-empty runq 1613 * that is NOT dd. Also require that the moving of the highest-load thread 1614 * from rdd to dd does not cause the uload's to cross each other. 1615 * 1616 * This is used by the thread chooser when the current cpu's queues are 1617 * empty to steal a thread from another cpu's queue. We want to offload 1618 * the most heavily-loaded queue. 1619 */ 1620 static 1621 dfly_pcpu_t 1622 dfly_choose_worst_queue(dfly_pcpu_t dd) 1623 { 1624 cpumask_t mask; 1625 cpu_node_t *cpup; 1626 cpu_node_t *cpun; 1627 cpu_node_t *cpub; 1628 dfly_pcpu_t rdd; 1629 int cpuid; 1630 int n; 1631 int count; 1632 int load; 1633 #if 0 1634 int pri; 1635 int hpri; 1636 #endif 1637 int highest_load; 1638 1639 /* 1640 * When the topology is unknown choose a random cpu that is hopefully 1641 * idle. 1642 */ 1643 if (dd->cpunode == NULL) { 1644 return (NULL); 1645 } 1646 1647 /* 1648 * When the topology is known choose a cpu whos group has, in 1649 * aggregate, has the lowest weighted load. 1650 */ 1651 cpup = root_cpu_node; 1652 rdd = dd; 1653 while (cpup) { 1654 /* 1655 * Degenerate case super-root 1656 */ 1657 if (cpup->child_node && cpup->child_no == 1) { 1658 cpup = cpup->child_node; 1659 continue; 1660 } 1661 1662 /* 1663 * Terminal cpunode 1664 */ 1665 if (cpup->child_node == NULL) { 1666 rdd = &dfly_pcpu[BSFCPUMASK(cpup->members)]; 1667 break; 1668 } 1669 1670 cpub = NULL; 1671 highest_load = 0; 1672 1673 for (n = 0; n < cpup->child_no; ++n) { 1674 /* 1675 * Accumulate load information for all cpus 1676 * which are members of this node. 1677 */ 1678 cpun = &cpup->child_node[n]; 1679 mask = cpun->members & usched_global_cpumask & 1680 smp_active_mask; 1681 if (mask == 0) 1682 continue; 1683 count = 0; 1684 load = 0; 1685 1686 while (mask) { 1687 cpuid = BSFCPUMASK(mask); 1688 rdd = &dfly_pcpu[cpuid]; 1689 load += rdd->uload; 1690 load += rdd->ucount * usched_dfly_weight3; 1691 if (rdd->uschedcp == NULL && 1692 rdd->runqcount == 0 && 1693 globaldata_find(cpuid)->gd_tdrunqcount == 0 1694 ) { 1695 load -= usched_dfly_weight4; 1696 } 1697 #if 0 1698 else if (rdd->upri > dd->upri + PPQ) { 1699 load -= usched_dfly_weight4 / 2; 1700 } 1701 #endif 1702 mask &= ~CPUMASK(cpuid); 1703 ++count; 1704 } 1705 load /= count; 1706 1707 /* 1708 * Prefer candidates which are somewhat closer to 1709 * our cpu. 1710 */ 1711 if (dd->cpumask & cpun->members) 1712 load += usched_dfly_weight1; 1713 1714 /* 1715 * The best candidate is the one with the worst 1716 * (highest) load. 1717 */ 1718 if (cpub == NULL || highest_load < load) { 1719 highest_load = load; 1720 cpub = cpun; 1721 } 1722 } 1723 cpup = cpub; 1724 } 1725 1726 /* 1727 * We never return our own node (dd), and only return a remote 1728 * node if it's load is significantly worse than ours (i.e. where 1729 * stealing a thread would be considered reasonable). 1730 * 1731 * This also helps us avoid breaking paired threads apart which 1732 * can have disastrous effects on performance. 1733 */ 1734 if (rdd == dd) 1735 return(NULL); 1736 1737 #if 0 1738 hpri = 0; 1739 if (rdd->rtqueuebits && hpri < (pri = bsrl(rdd->rtqueuebits))) 1740 hpri = pri; 1741 if (rdd->queuebits && hpri < (pri = bsrl(rdd->queuebits))) 1742 hpri = pri; 1743 if (rdd->idqueuebits && hpri < (pri = bsrl(rdd->idqueuebits))) 1744 hpri = pri; 1745 hpri *= PPQ; 1746 if (rdd->uload - hpri < dd->uload + hpri) 1747 return(NULL); 1748 #endif 1749 return (rdd); 1750 } 1751 1752 static 1753 dfly_pcpu_t 1754 dfly_choose_queue_simple(dfly_pcpu_t dd, struct lwp *lp) 1755 { 1756 dfly_pcpu_t rdd; 1757 cpumask_t tmpmask; 1758 cpumask_t mask; 1759 int cpuid; 1760 1761 /* 1762 * Fallback to the original heuristic, select random cpu, 1763 * first checking cpus not currently running a user thread. 1764 */ 1765 ++dfly_scancpu; 1766 cpuid = (dfly_scancpu & 0xFFFF) % ncpus; 1767 mask = ~dfly_curprocmask & dfly_rdyprocmask & lp->lwp_cpumask & 1768 smp_active_mask & usched_global_cpumask; 1769 1770 while (mask) { 1771 tmpmask = ~(CPUMASK(cpuid) - 1); 1772 if (mask & tmpmask) 1773 cpuid = BSFCPUMASK(mask & tmpmask); 1774 else 1775 cpuid = BSFCPUMASK(mask); 1776 rdd = &dfly_pcpu[cpuid]; 1777 1778 if ((rdd->upri & ~PPQMASK) >= (lp->lwp_priority & ~PPQMASK)) 1779 goto found; 1780 mask &= ~CPUMASK(cpuid); 1781 } 1782 1783 /* 1784 * Then cpus which might have a currently running lp 1785 */ 1786 cpuid = (dfly_scancpu & 0xFFFF) % ncpus; 1787 mask = dfly_curprocmask & dfly_rdyprocmask & 1788 lp->lwp_cpumask & smp_active_mask & usched_global_cpumask; 1789 1790 while (mask) { 1791 tmpmask = ~(CPUMASK(cpuid) - 1); 1792 if (mask & tmpmask) 1793 cpuid = BSFCPUMASK(mask & tmpmask); 1794 else 1795 cpuid = BSFCPUMASK(mask); 1796 rdd = &dfly_pcpu[cpuid]; 1797 1798 if ((rdd->upri & ~PPQMASK) > (lp->lwp_priority & ~PPQMASK)) 1799 goto found; 1800 mask &= ~CPUMASK(cpuid); 1801 } 1802 1803 /* 1804 * If we cannot find a suitable cpu we reload from dfly_scancpu 1805 * and round-robin. Other cpus will pickup as they release their 1806 * current lwps or become ready. 1807 * 1808 * Avoid a degenerate system lockup case if usched_global_cpumask 1809 * is set to 0 or otherwise does not cover lwp_cpumask. 1810 * 1811 * We only kick the target helper thread in this case, we do not 1812 * set the user resched flag because 1813 */ 1814 cpuid = (dfly_scancpu & 0xFFFF) % ncpus; 1815 if ((CPUMASK(cpuid) & usched_global_cpumask) == 0) 1816 cpuid = 0; 1817 rdd = &dfly_pcpu[cpuid]; 1818 found: 1819 return (rdd); 1820 } 1821 1822 static 1823 void 1824 dfly_need_user_resched_remote(void *dummy) 1825 { 1826 globaldata_t gd = mycpu; 1827 dfly_pcpu_t dd = &dfly_pcpu[gd->gd_cpuid]; 1828 1829 /* 1830 * Flag reschedule needed 1831 */ 1832 need_user_resched(); 1833 1834 /* 1835 * If no user thread is currently running we need to kick the helper 1836 * on our cpu to recover. Otherwise the cpu will never schedule 1837 * anything again. 1838 * 1839 * We cannot schedule the process ourselves because this is an 1840 * IPI callback and we cannot acquire spinlocks in an IPI callback. 1841 * 1842 * Call wakeup_mycpu to avoid sending IPIs to other CPUs 1843 */ 1844 if (dd->uschedcp == NULL && (dfly_rdyprocmask & gd->gd_cpumask)) { 1845 atomic_clear_cpumask(&dfly_rdyprocmask, gd->gd_cpumask); 1846 wakeup_mycpu(&dd->helper_thread); 1847 } 1848 } 1849 1850 #endif 1851 1852 /* 1853 * dfly_remrunqueue_locked() removes a given process from the run queue 1854 * that it is on, clearing the queue busy bit if it becomes empty. 1855 * 1856 * Note that user process scheduler is different from the LWKT schedule. 1857 * The user process scheduler only manages user processes but it uses LWKT 1858 * underneath, and a user process operating in the kernel will often be 1859 * 'released' from our management. 1860 * 1861 * uload is NOT adjusted here. It is only adjusted if the lwkt_thread goes 1862 * to sleep or the lwp is moved to a different runq. 1863 */ 1864 static void 1865 dfly_remrunqueue_locked(dfly_pcpu_t rdd, struct lwp *lp) 1866 { 1867 struct rq *q; 1868 u_int32_t *which; 1869 u_int8_t pri; 1870 1871 KKASSERT(rdd->runqcount >= 0); 1872 1873 pri = lp->lwp_rqindex; 1874 1875 switch(lp->lwp_rqtype) { 1876 case RTP_PRIO_NORMAL: 1877 q = &rdd->queues[pri]; 1878 which = &rdd->queuebits; 1879 break; 1880 case RTP_PRIO_REALTIME: 1881 case RTP_PRIO_FIFO: 1882 q = &rdd->rtqueues[pri]; 1883 which = &rdd->rtqueuebits; 1884 break; 1885 case RTP_PRIO_IDLE: 1886 q = &rdd->idqueues[pri]; 1887 which = &rdd->idqueuebits; 1888 break; 1889 default: 1890 panic("remrunqueue: invalid rtprio type"); 1891 /* NOT REACHED */ 1892 } 1893 KKASSERT(lp->lwp_mpflags & LWP_MP_ONRUNQ); 1894 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ); 1895 TAILQ_REMOVE(q, lp, lwp_procq); 1896 --rdd->runqcount; 1897 if (TAILQ_EMPTY(q)) { 1898 KASSERT((*which & (1 << pri)) != 0, 1899 ("remrunqueue: remove from empty queue")); 1900 *which &= ~(1 << pri); 1901 } 1902 } 1903 1904 /* 1905 * dfly_setrunqueue_locked() 1906 * 1907 * Add a process whos rqtype and rqindex had previously been calculated 1908 * onto the appropriate run queue. Determine if the addition requires 1909 * a reschedule on a cpu and return the cpuid or -1. 1910 * 1911 * NOTE: Lower priorities are better priorities. 1912 * 1913 * NOTE ON ULOAD: This variable specifies the aggregate load on a cpu, the 1914 * sum of the rough lwp_priority for all running and runnable 1915 * processes. Lower priority processes (higher lwp_priority 1916 * values) actually DO count as more load, not less, because 1917 * these are the programs which require the most care with 1918 * regards to cpu selection. 1919 */ 1920 static void 1921 dfly_setrunqueue_locked(dfly_pcpu_t rdd, struct lwp *lp) 1922 { 1923 struct rq *q; 1924 u_int32_t *which; 1925 int pri; 1926 1927 KKASSERT(lp->lwp_qcpu == rdd->cpuid); 1928 1929 if ((lp->lwp_mpflags & LWP_MP_ULOAD) == 0) { 1930 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ULOAD); 1931 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].uload, lp->lwp_uload); 1932 atomic_add_int(&dfly_pcpu[lp->lwp_qcpu].ucount, 1); 1933 atomic_add_int(&dfly_ucount, 1); 1934 } 1935 1936 pri = lp->lwp_rqindex; 1937 1938 switch(lp->lwp_rqtype) { 1939 case RTP_PRIO_NORMAL: 1940 q = &rdd->queues[pri]; 1941 which = &rdd->queuebits; 1942 break; 1943 case RTP_PRIO_REALTIME: 1944 case RTP_PRIO_FIFO: 1945 q = &rdd->rtqueues[pri]; 1946 which = &rdd->rtqueuebits; 1947 break; 1948 case RTP_PRIO_IDLE: 1949 q = &rdd->idqueues[pri]; 1950 which = &rdd->idqueuebits; 1951 break; 1952 default: 1953 panic("remrunqueue: invalid rtprio type"); 1954 /* NOT REACHED */ 1955 } 1956 1957 /* 1958 * Place us on the selected queue. Determine if we should be 1959 * placed at the head of the queue or at the end. 1960 * 1961 * We are placed at the tail if our round-robin count has expired, 1962 * or is about to expire and the system thinks its a good place to 1963 * round-robin, or there is already a next thread on the queue 1964 * (it might be trying to pick up where it left off and we don't 1965 * want to interfere). 1966 */ 1967 KKASSERT((lp->lwp_mpflags & LWP_MP_ONRUNQ) == 0); 1968 atomic_set_int(&lp->lwp_mpflags, LWP_MP_ONRUNQ); 1969 ++rdd->runqcount; 1970 1971 if (lp->lwp_rrcount >= usched_dfly_rrinterval || 1972 (lp->lwp_rrcount >= usched_dfly_rrinterval / 2 && 1973 (lp->lwp_thread->td_mpflags & TDF_MP_BATCH_DEMARC)) || 1974 !TAILQ_EMPTY(q) 1975 ) { 1976 atomic_clear_int(&lp->lwp_thread->td_mpflags, 1977 TDF_MP_BATCH_DEMARC); 1978 lp->lwp_rrcount = 0; 1979 TAILQ_INSERT_TAIL(q, lp, lwp_procq); 1980 } else { 1981 if (TAILQ_EMPTY(q)) 1982 lp->lwp_rrcount = 0; 1983 TAILQ_INSERT_HEAD(q, lp, lwp_procq); 1984 } 1985 *which |= 1 << pri; 1986 } 1987 1988 #ifdef SMP 1989 1990 /* 1991 * For SMP systems a user scheduler helper thread is created for each 1992 * cpu and is used to allow one cpu to wakeup another for the purposes of 1993 * scheduling userland threads from setrunqueue(). 1994 * 1995 * UP systems do not need the helper since there is only one cpu. 1996 * 1997 * We can't use the idle thread for this because we might block. 1998 * Additionally, doing things this way allows us to HLT idle cpus 1999 * on MP systems. 2000 */ 2001 static void 2002 dfly_helper_thread(void *dummy) 2003 { 2004 globaldata_t gd; 2005 dfly_pcpu_t dd; 2006 dfly_pcpu_t rdd; 2007 struct lwp *nlp; 2008 cpumask_t mask; 2009 int cpuid; 2010 2011 gd = mycpu; 2012 cpuid = gd->gd_cpuid; /* doesn't change */ 2013 mask = gd->gd_cpumask; /* doesn't change */ 2014 dd = &dfly_pcpu[cpuid]; 2015 2016 /* 2017 * Since we only want to be woken up only when no user processes 2018 * are scheduled on a cpu, run at an ultra low priority. 2019 */ 2020 lwkt_setpri_self(TDPRI_USER_SCHEDULER); 2021 2022 tsleep(&dd->helper_thread, 0, "schslp", 0); 2023 2024 for (;;) { 2025 /* 2026 * We use the LWKT deschedule-interlock trick to avoid racing 2027 * dfly_rdyprocmask. This means we cannot block through to the 2028 * manual lwkt_switch() call we make below. 2029 */ 2030 crit_enter_gd(gd); 2031 tsleep_interlock(&dd->helper_thread, 0); 2032 2033 spin_lock(&dd->spin); 2034 2035 atomic_set_cpumask(&dfly_rdyprocmask, mask); 2036 clear_user_resched(); /* This satisfied the reschedule request */ 2037 #if 0 2038 dd->rrcount = 0; /* Reset the round-robin counter */ 2039 #endif 2040 2041 if (dd->runqcount || dd->uschedcp != NULL) { 2042 /* 2043 * Threads are available. A thread may or may not be 2044 * currently scheduled. Get the best thread already queued 2045 * to this cpu. 2046 */ 2047 nlp = dfly_chooseproc_locked(dd, dd, dd->uschedcp, 0); 2048 if (nlp) { 2049 atomic_set_cpumask(&dfly_curprocmask, mask); 2050 dd->upri = nlp->lwp_priority; 2051 dd->uschedcp = nlp; 2052 #if 0 2053 dd->rrcount = 0; /* reset round robin */ 2054 #endif 2055 spin_unlock(&dd->spin); 2056 lwkt_acquire(nlp->lwp_thread); 2057 lwkt_schedule(nlp->lwp_thread); 2058 } else { 2059 /* 2060 * This situation should not occur because we had 2061 * at least one thread available. 2062 */ 2063 spin_unlock(&dd->spin); 2064 } 2065 } else if (usched_dfly_features & 0x01) { 2066 /* 2067 * This cpu is devoid of runnable threads, steal a thread 2068 * from another cpu. Since we're stealing, might as well 2069 * load balance at the same time. 2070 * 2071 * We choose the highest-loaded thread from the worst queue. 2072 * 2073 * NOTE! This function only returns a non-NULL rdd when 2074 * another cpu's queue is obviously overloaded. We 2075 * do not want to perform the type of rebalancing 2076 * the schedclock does here because it would result 2077 * in insane process pulling when 'steady' state is 2078 * partially unbalanced (e.g. 6 runnables and only 2079 * 4 cores). 2080 */ 2081 rdd = dfly_choose_worst_queue(dd); 2082 if (rdd && spin_trylock(&rdd->spin)) { 2083 nlp = dfly_chooseproc_locked(rdd, dd, NULL, 1); 2084 spin_unlock(&rdd->spin); 2085 } else { 2086 nlp = NULL; 2087 } 2088 if (nlp) { 2089 atomic_set_cpumask(&dfly_curprocmask, mask); 2090 dd->upri = nlp->lwp_priority; 2091 dd->uschedcp = nlp; 2092 #if 0 2093 dd->rrcount = 0; /* reset round robin */ 2094 #endif 2095 spin_unlock(&dd->spin); 2096 lwkt_acquire(nlp->lwp_thread); 2097 lwkt_schedule(nlp->lwp_thread); 2098 } else { 2099 /* 2100 * Leave the thread on our run queue. Another 2101 * scheduler will try to pull it later. 2102 */ 2103 spin_unlock(&dd->spin); 2104 } 2105 } else { 2106 /* 2107 * devoid of runnable threads and not allowed to steal 2108 * any. 2109 */ 2110 spin_unlock(&dd->spin); 2111 } 2112 2113 /* 2114 * We're descheduled unless someone scheduled us. Switch away. 2115 * Exiting the critical section will cause splz() to be called 2116 * for us if interrupts and such are pending. 2117 */ 2118 crit_exit_gd(gd); 2119 tsleep(&dd->helper_thread, PINTERLOCKED, "schslp", 0); 2120 } 2121 } 2122 2123 #if 0 2124 static int 2125 sysctl_usched_dfly_stick_to_level(SYSCTL_HANDLER_ARGS) 2126 { 2127 int error, new_val; 2128 2129 new_val = usched_dfly_stick_to_level; 2130 2131 error = sysctl_handle_int(oidp, &new_val, 0, req); 2132 if (error != 0 || req->newptr == NULL) 2133 return (error); 2134 if (new_val > cpu_topology_levels_number - 1 || new_val < 0) 2135 return (EINVAL); 2136 usched_dfly_stick_to_level = new_val; 2137 return (0); 2138 } 2139 #endif 2140 2141 /* 2142 * Setup our scheduler helpers. Note that curprocmask bit 0 has already 2143 * been cleared by rqinit() and we should not mess with it further. 2144 */ 2145 static void 2146 dfly_helper_thread_cpu_init(void) 2147 { 2148 int i; 2149 int j; 2150 int cpuid; 2151 int smt_not_supported = 0; 2152 int cache_coherent_not_supported = 0; 2153 2154 if (bootverbose) 2155 kprintf("Start scheduler helpers on cpus:\n"); 2156 2157 sysctl_ctx_init(&usched_dfly_sysctl_ctx); 2158 usched_dfly_sysctl_tree = 2159 SYSCTL_ADD_NODE(&usched_dfly_sysctl_ctx, 2160 SYSCTL_STATIC_CHILDREN(_kern), OID_AUTO, 2161 "usched_dfly", CTLFLAG_RD, 0, ""); 2162 2163 for (i = 0; i < ncpus; ++i) { 2164 dfly_pcpu_t dd = &dfly_pcpu[i]; 2165 cpumask_t mask = CPUMASK(i); 2166 2167 if ((mask & smp_active_mask) == 0) 2168 continue; 2169 2170 spin_init(&dd->spin); 2171 dd->cpunode = get_cpu_node_by_cpuid(i); 2172 dd->cpuid = i; 2173 dd->cpumask = CPUMASK(i); 2174 for (j = 0; j < NQS; j++) { 2175 TAILQ_INIT(&dd->queues[j]); 2176 TAILQ_INIT(&dd->rtqueues[j]); 2177 TAILQ_INIT(&dd->idqueues[j]); 2178 } 2179 atomic_clear_cpumask(&dfly_curprocmask, 1); 2180 2181 if (dd->cpunode == NULL) { 2182 smt_not_supported = 1; 2183 cache_coherent_not_supported = 1; 2184 if (bootverbose) 2185 kprintf ("\tcpu%d - WARNING: No CPU NODE " 2186 "found for cpu\n", i); 2187 } else { 2188 switch (dd->cpunode->type) { 2189 case THREAD_LEVEL: 2190 if (bootverbose) 2191 kprintf ("\tcpu%d - HyperThreading " 2192 "available. Core siblings: ", 2193 i); 2194 break; 2195 case CORE_LEVEL: 2196 smt_not_supported = 1; 2197 2198 if (bootverbose) 2199 kprintf ("\tcpu%d - No HT available, " 2200 "multi-core/physical " 2201 "cpu. Physical siblings: ", 2202 i); 2203 break; 2204 case CHIP_LEVEL: 2205 smt_not_supported = 1; 2206 2207 if (bootverbose) 2208 kprintf ("\tcpu%d - No HT available, " 2209 "single-core/physical cpu. " 2210 "Package Siblings: ", 2211 i); 2212 break; 2213 default: 2214 /* Let's go for safe defaults here */ 2215 smt_not_supported = 1; 2216 cache_coherent_not_supported = 1; 2217 if (bootverbose) 2218 kprintf ("\tcpu%d - Unknown cpunode->" 2219 "type=%u. Siblings: ", 2220 i, 2221 (u_int)dd->cpunode->type); 2222 break; 2223 } 2224 2225 if (bootverbose) { 2226 if (dd->cpunode->parent_node != NULL) { 2227 CPUSET_FOREACH(cpuid, dd->cpunode->parent_node->members) 2228 kprintf("cpu%d ", cpuid); 2229 kprintf("\n"); 2230 } else { 2231 kprintf(" no siblings\n"); 2232 } 2233 } 2234 } 2235 2236 lwkt_create(dfly_helper_thread, NULL, NULL, &dd->helper_thread, 2237 0, i, "usched %d", i); 2238 2239 /* 2240 * Allow user scheduling on the target cpu. cpu #0 has already 2241 * been enabled in rqinit(). 2242 */ 2243 if (i) 2244 atomic_clear_cpumask(&dfly_curprocmask, mask); 2245 atomic_set_cpumask(&dfly_rdyprocmask, mask); 2246 dd->upri = PRIBASE_NULL; 2247 2248 } 2249 2250 /* usched_dfly sysctl configurable parameters */ 2251 2252 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2253 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2254 OID_AUTO, "rrinterval", CTLFLAG_RW, 2255 &usched_dfly_rrinterval, 0, ""); 2256 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2257 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2258 OID_AUTO, "decay", CTLFLAG_RW, 2259 &usched_dfly_decay, 0, "Extra decay when not running"); 2260 2261 /* Add enable/disable option for SMT scheduling if supported */ 2262 if (smt_not_supported) { 2263 usched_dfly_smt = 0; 2264 SYSCTL_ADD_STRING(&usched_dfly_sysctl_ctx, 2265 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2266 OID_AUTO, "smt", CTLFLAG_RD, 2267 "NOT SUPPORTED", 0, "SMT NOT SUPPORTED"); 2268 } else { 2269 usched_dfly_smt = 1; 2270 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2271 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2272 OID_AUTO, "smt", CTLFLAG_RW, 2273 &usched_dfly_smt, 0, "Enable SMT scheduling"); 2274 } 2275 2276 /* 2277 * Add enable/disable option for cache coherent scheduling 2278 * if supported 2279 */ 2280 if (cache_coherent_not_supported) { 2281 usched_dfly_cache_coherent = 0; 2282 SYSCTL_ADD_STRING(&usched_dfly_sysctl_ctx, 2283 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2284 OID_AUTO, "cache_coherent", CTLFLAG_RD, 2285 "NOT SUPPORTED", 0, 2286 "Cache coherence NOT SUPPORTED"); 2287 } else { 2288 usched_dfly_cache_coherent = 1; 2289 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2290 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2291 OID_AUTO, "cache_coherent", CTLFLAG_RW, 2292 &usched_dfly_cache_coherent, 0, 2293 "Enable/Disable cache coherent scheduling"); 2294 2295 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2296 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2297 OID_AUTO, "weight1", CTLFLAG_RW, 2298 &usched_dfly_weight1, 200, 2299 "Weight selection for current cpu"); 2300 2301 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2302 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2303 OID_AUTO, "weight2", CTLFLAG_RW, 2304 &usched_dfly_weight2, 180, 2305 "Weight selection for wakefrom cpu"); 2306 2307 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2308 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2309 OID_AUTO, "weight3", CTLFLAG_RW, 2310 &usched_dfly_weight3, 40, 2311 "Weight selection for num threads on queue"); 2312 2313 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2314 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2315 OID_AUTO, "weight4", CTLFLAG_RW, 2316 &usched_dfly_weight4, 160, 2317 "Availability of other idle cpus"); 2318 2319 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2320 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2321 OID_AUTO, "fast_resched", CTLFLAG_RW, 2322 &usched_dfly_fast_resched, 0, 2323 "Availability of other idle cpus"); 2324 2325 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2326 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2327 OID_AUTO, "features", CTLFLAG_RW, 2328 &usched_dfly_features, 0x8F, 2329 "Allow pulls into empty queues"); 2330 2331 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2332 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2333 OID_AUTO, "swmask", CTLFLAG_RW, 2334 &usched_dfly_swmask, ~PPQMASK, 2335 "Queue mask to force thread switch"); 2336 2337 2338 #if 0 2339 SYSCTL_ADD_PROC(&usched_dfly_sysctl_ctx, 2340 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2341 OID_AUTO, "stick_to_level", 2342 CTLTYPE_INT | CTLFLAG_RW, 2343 NULL, sizeof usched_dfly_stick_to_level, 2344 sysctl_usched_dfly_stick_to_level, "I", 2345 "Stick a process to this level. See sysctl" 2346 "paremter hw.cpu_topology.level_description"); 2347 #endif 2348 } 2349 } 2350 SYSINIT(uschedtd, SI_BOOT2_USCHED, SI_ORDER_SECOND, 2351 dfly_helper_thread_cpu_init, NULL) 2352 2353 #else /* No SMP options - just add the configurable parameters to sysctl */ 2354 2355 static void 2356 sched_sysctl_tree_init(void) 2357 { 2358 sysctl_ctx_init(&usched_dfly_sysctl_ctx); 2359 usched_dfly_sysctl_tree = 2360 SYSCTL_ADD_NODE(&usched_dfly_sysctl_ctx, 2361 SYSCTL_STATIC_CHILDREN(_kern), OID_AUTO, 2362 "usched_dfly", CTLFLAG_RD, 0, ""); 2363 2364 /* usched_dfly sysctl configurable parameters */ 2365 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2366 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2367 OID_AUTO, "rrinterval", CTLFLAG_RW, 2368 &usched_dfly_rrinterval, 0, ""); 2369 SYSCTL_ADD_INT(&usched_dfly_sysctl_ctx, 2370 SYSCTL_CHILDREN(usched_dfly_sysctl_tree), 2371 OID_AUTO, "decay", CTLFLAG_RW, 2372 &usched_dfly_decay, 0, "Extra decay when not running"); 2373 } 2374 SYSINIT(uschedtd, SI_BOOT2_USCHED, SI_ORDER_SECOND, 2375 sched_sysctl_tree_init, NULL) 2376 #endif 2377