1*86d7f5d3SJohn Marino /*
2*86d7f5d3SJohn Marino * mutex3.c
3*86d7f5d3SJohn Marino *
4*86d7f5d3SJohn Marino * $DragonFly: src/test/sysperf/mutex3.c,v 1.1 2006/05/18 02:22:46 dillon Exp $
5*86d7f5d3SJohn Marino */
6*86d7f5d3SJohn Marino
7*86d7f5d3SJohn Marino #include "blib.h"
8*86d7f5d3SJohn Marino
9*86d7f5d3SJohn Marino #include <sys/types.h>
10*86d7f5d3SJohn Marino #include <machine/atomic.h>
11*86d7f5d3SJohn Marino #include <machine/cpufunc.h>
12*86d7f5d3SJohn Marino
13*86d7f5d3SJohn Marino int *mtx;
14*86d7f5d3SJohn Marino int refcnt;
15*86d7f5d3SJohn Marino
16*86d7f5d3SJohn Marino static void
spin_lock_contested(void)17*86d7f5d3SJohn Marino spin_lock_contested(void)
18*86d7f5d3SJohn Marino {
19*86d7f5d3SJohn Marino int i;
20*86d7f5d3SJohn Marino int j;
21*86d7f5d3SJohn Marino
22*86d7f5d3SJohn Marino j = 1;
23*86d7f5d3SJohn Marino while (atomic_swap_int(mtx, 1) != 0) {
24*86d7f5d3SJohn Marino for (i = 0; i < j; ++i)
25*86d7f5d3SJohn Marino __asm __volatile("pause"::);
26*86d7f5d3SJohn Marino j <<= 1;
27*86d7f5d3SJohn Marino }
28*86d7f5d3SJohn Marino }
29*86d7f5d3SJohn Marino
30*86d7f5d3SJohn Marino static __inline void
spin_lock(void)31*86d7f5d3SJohn Marino spin_lock(void)
32*86d7f5d3SJohn Marino {
33*86d7f5d3SJohn Marino if (refcnt == 1) {
34*86d7f5d3SJohn Marino if (*mtx == 0)
35*86d7f5d3SJohn Marino *mtx = 1;
36*86d7f5d3SJohn Marino else
37*86d7f5d3SJohn Marino spin_lock_contested();
38*86d7f5d3SJohn Marino } else if (atomic_swap_int(mtx, 1) != 0) {
39*86d7f5d3SJohn Marino spin_lock_contested();
40*86d7f5d3SJohn Marino }
41*86d7f5d3SJohn Marino }
42*86d7f5d3SJohn Marino
43*86d7f5d3SJohn Marino static __inline void
spin_unlock(void)44*86d7f5d3SJohn Marino spin_unlock(void)
45*86d7f5d3SJohn Marino {
46*86d7f5d3SJohn Marino cpu_sfence();
47*86d7f5d3SJohn Marino *mtx = 0;
48*86d7f5d3SJohn Marino }
49*86d7f5d3SJohn Marino
50*86d7f5d3SJohn Marino int
main(int ac,char ** av)51*86d7f5d3SJohn Marino main(int ac, char **av)
52*86d7f5d3SJohn Marino {
53*86d7f5d3SJohn Marino long long count = 0;
54*86d7f5d3SJohn Marino long long max;
55*86d7f5d3SJohn Marino int j;
56*86d7f5d3SJohn Marino int *counter;
57*86d7f5d3SJohn Marino pid_t pid;
58*86d7f5d3SJohn Marino
59*86d7f5d3SJohn Marino printf("Test simple locked bus cycle mutex latency\n");
60*86d7f5d3SJohn Marino printf("auto-forks two processes for the test with shared memory\n");
61*86d7f5d3SJohn Marino printf("This test is only useful on a SMP box\n");
62*86d7f5d3SJohn Marino
63*86d7f5d3SJohn Marino start_timing();
64*86d7f5d3SJohn Marino mtx = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANON, -1, 0);
65*86d7f5d3SJohn Marino counter = mtx + 64;
66*86d7f5d3SJohn Marino while (stop_timing(0, NULL) == 0) {
67*86d7f5d3SJohn Marino for (j = 0; j < 100; ++j) {
68*86d7f5d3SJohn Marino spin_lock();
69*86d7f5d3SJohn Marino spin_unlock();
70*86d7f5d3SJohn Marino }
71*86d7f5d3SJohn Marino count += 100;
72*86d7f5d3SJohn Marino }
73*86d7f5d3SJohn Marino max = count;
74*86d7f5d3SJohn Marino *mtx = 0;
75*86d7f5d3SJohn Marino
76*86d7f5d3SJohn Marino refcnt = 1;
77*86d7f5d3SJohn Marino start_timing();
78*86d7f5d3SJohn Marino for (count = 0; count < max; count += 100) {
79*86d7f5d3SJohn Marino for (j = 0; j < 100; ++j) {
80*86d7f5d3SJohn Marino spin_lock();
81*86d7f5d3SJohn Marino spin_unlock(); /* release */
82*86d7f5d3SJohn Marino ++counter[64];
83*86d7f5d3SJohn Marino }
84*86d7f5d3SJohn Marino }
85*86d7f5d3SJohn Marino stop_timing(count, "complex_mtx(uncontested/1cpu)");
86*86d7f5d3SJohn Marino refcnt = 2;
87*86d7f5d3SJohn Marino
88*86d7f5d3SJohn Marino if ((pid = fork()) == 0) {
89*86d7f5d3SJohn Marino for (;;) {
90*86d7f5d3SJohn Marino for (j = 0; j < 100; ++j) {
91*86d7f5d3SJohn Marino spin_lock();
92*86d7f5d3SJohn Marino spin_unlock(); /* release */
93*86d7f5d3SJohn Marino ++counter[128];
94*86d7f5d3SJohn Marino }
95*86d7f5d3SJohn Marino }
96*86d7f5d3SJohn Marino } else {
97*86d7f5d3SJohn Marino start_timing();
98*86d7f5d3SJohn Marino for (count = 0; count < max; count += 100) {
99*86d7f5d3SJohn Marino for (j = 0; j < 100; ++j) {
100*86d7f5d3SJohn Marino spin_lock();
101*86d7f5d3SJohn Marino spin_unlock(); /* release */
102*86d7f5d3SJohn Marino ++counter[64];
103*86d7f5d3SJohn Marino }
104*86d7f5d3SJohn Marino }
105*86d7f5d3SJohn Marino stop_timing(count, "complex_mtx");
106*86d7f5d3SJohn Marino printf("proc1=%d proc2=%d\n", counter[64], counter[128]);
107*86d7f5d3SJohn Marino kill(pid, 9);
108*86d7f5d3SJohn Marino }
109*86d7f5d3SJohn Marino return(0);
110*86d7f5d3SJohn Marino }
111*86d7f5d3SJohn Marino
112