ceph/src/dpdk/lib/librte_eal/common/eal_common_timer.c

   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 */
  48 static uint64_t eal_tsc_resolution_hz;
  49
  50 /* Pointer to user delay function */
  51 void (*rte_delay_us)(unsigned int) = NULL;
  52
  53 void
  54 rte_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
  62 uint64_t
  63 rte_get_tsc_hz(void)
  64 {
  65         return eal_tsc_resolution_hz;
  66 }
  67
  68 static uint64_t
  69 estimate_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
  79 void
  80 set_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
  91 void rte_delay_us_callback_register(void (*userfunc)(unsigned int))
  92 {
  93         rte_delay_us = userfunc;
  94 }
  95
  96 static void __attribute__((constructor))
  97 rte_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 }