lib/librte_eal/common/eal_common_timer.c

   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 }