lib/eal/common/eal_common_timer.c

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