xref: /dpdk/lib/eal/common/eal_common_timer.c (revision daa02b5cddbb8e11b31d41e2bf7bb1ae64dcae2f)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation
3  */
4 
5 #include <string.h>
6 #include <stdio.h>
7 #include <unistd.h>
8 #include <inttypes.h>
9 #include <sys/types.h>
10 #include <time.h>
11 #include <errno.h>
12 
13 #include <rte_common.h>
14 #include <rte_compat.h>
15 #include <rte_log.h>
16 #include <rte_cycles.h>
17 #include <rte_pause.h>
18 #include <rte_eal.h>
19 
20 #include "eal_private.h"
21 #include "eal_memcfg.h"
22 
23 /* The frequency of the RDTSC timer resolution */
24 static uint64_t eal_tsc_resolution_hz;
25 
26 /* Pointer to user delay function */
27 void (*rte_delay_us)(unsigned int) = NULL;
28 
29 void
30 rte_delay_us_block(unsigned int us)
31 {
32 	const uint64_t start = rte_get_timer_cycles();
33 	const uint64_t ticks = (uint64_t)us * rte_get_timer_hz() / 1E6;
34 	while ((rte_get_timer_cycles() - start) < ticks)
35 		rte_pause();
36 }
37 
38 uint64_t
39 rte_get_tsc_hz(void)
40 {
41 	return eal_tsc_resolution_hz;
42 }
43 
44 static uint64_t
45 estimate_tsc_freq(void)
46 {
47 #define CYC_PER_10MHZ 1E7
48 	RTE_LOG(WARNING, EAL, "WARNING: TSC frequency estimated roughly"
49 		" - clock timings may be less accurate.\n");
50 	/* assume that the rte_delay_us_sleep() will sleep for 1 second */
51 	uint64_t start = rte_rdtsc();
52 	rte_delay_us_sleep(US_PER_S);
53 	/* Round up to 10Mhz. 1E7 ~ 10Mhz */
54 	return RTE_ALIGN_MUL_NEAR(rte_rdtsc() - start, CYC_PER_10MHZ);
55 }
56 
57 void
58 set_tsc_freq(void)
59 {
60 	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
61 	uint64_t freq;
62 
63 	if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
64 		/*
65 		 * Just use the primary process calculated TSC rate in any
66 		 * secondary process.  It avoids any unnecessary overhead on
67 		 * systems where arch-specific frequency detection is not
68 		 * available.
69 		 */
70 		eal_tsc_resolution_hz = mcfg->tsc_hz;
71 		return;
72 	}
73 
74 	freq = get_tsc_freq_arch();
75 	if (!freq)
76 		freq = get_tsc_freq();
77 	if (!freq)
78 		freq = estimate_tsc_freq();
79 
80 	RTE_LOG(DEBUG, EAL, "TSC frequency is ~%" PRIu64 " KHz\n", freq / 1000);
81 	eal_tsc_resolution_hz = freq;
82 	mcfg->tsc_hz = freq;
83 }
84 
85 void rte_delay_us_callback_register(void (*userfunc)(unsigned int))
86 {
87 	rte_delay_us = userfunc;
88 }
89 
90 RTE_INIT(rte_timer_init)
91 {
92 	/* set rte_delay_us_block as a delay function */
93 	rte_delay_us_callback_register(rte_delay_us_block);
94 }
95