eal_common_timer.c revision 3d9b7210
1/*-
2 *   BSD LICENSE
3 *
4 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
5 *   All rights reserved.
6 *
7 *   Redistribution and use in source and binary forms, with or without
8 *   modification, are permitted provided that the following conditions
9 *   are met:
10 *
11 *     * Redistributions of source code must retain the above copyright
12 *       notice, this list of conditions and the following disclaimer.
13 *     * Redistributions in binary form must reproduce the above copyright
14 *       notice, this list of conditions and the following disclaimer in
15 *       the documentation and/or other materials provided with the
16 *       distribution.
17 *     * Neither the name of Intel Corporation nor the names of its
18 *       contributors may be used to endorse or promote products derived
19 *       from this software without specific prior written permission.
20 *
21 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <string.h>
35#include <stdio.h>
36#include <unistd.h>
37#include <inttypes.h>
38#include <sys/types.h>
39#include <errno.h>
40
41#include <rte_common.h>
42#include <rte_log.h>
43#include <rte_cycles.h>
44
45#include "eal_private.h"
46
47/* The frequency of the RDTSC timer resolution */
48static uint64_t eal_tsc_resolution_hz;
49
50/* Pointer to user delay function */
51void (*rte_delay_us)(unsigned int) = NULL;
52
53void
54rte_delay_us_block(unsigned int us)
55{
56	const uint64_t start = rte_get_timer_cycles();
57	const uint64_t ticks = (uint64_t)us * rte_get_timer_hz() / 1E6;
58	while ((rte_get_timer_cycles() - start) < ticks)
59		rte_pause();
60}
61
62uint64_t
63rte_get_tsc_hz(void)
64{
65	return eal_tsc_resolution_hz;
66}
67
68static uint64_t
69estimate_tsc_freq(void)
70{
71	RTE_LOG(WARNING, EAL, "WARNING: TSC frequency estimated roughly"
72		" - clock timings may be less accurate.\n");
73	/* assume that the sleep(1) will sleep for 1 second */
74	uint64_t start = rte_rdtsc();
75	sleep(1);
76	return rte_rdtsc() - start;
77}
78
79void
80set_tsc_freq(void)
81{
82	uint64_t freq = get_tsc_freq();
83
84	if (!freq)
85		freq = estimate_tsc_freq();
86
87	RTE_LOG(DEBUG, EAL, "TSC frequency is ~%" PRIu64 " KHz\n", freq / 1000);
88	eal_tsc_resolution_hz = freq;
89}
90
91void rte_delay_us_callback_register(void (*userfunc)(unsigned int))
92{
93	rte_delay_us = userfunc;
94}
95
96static void __attribute__((constructor))
97rte_timer_init(void)
98{
99	/* set rte_delay_us_block as a delay function */
100	rte_delay_us_callback_register(rte_delay_us_block);
101}
102