lib/librte_eal/linux/eal/eal_timer.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation.
   3  * Copyright(c) 2012-2013 6WIND S.A.
   4  */
   5
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include <stdio.h>
   9 #include <stdint.h>
  10 #include <unistd.h>
  11 #include <fcntl.h>
  12 #include <inttypes.h>
  13 #include <sys/mman.h>
  14 #include <sys/queue.h>
  15 #include <pthread.h>
  16 #include <errno.h>
  17
  18 #include <rte_common.h>
  19 #include <rte_log.h>
  20 #include <rte_cycles.h>
  21 #include <rte_lcore.h>
  22 #include <rte_memory.h>
  23 #include <rte_eal.h>
  24 #include <rte_debug.h>
  25
  26 #include "eal_private.h"
  27 #include "eal_internal_cfg.h"
  28
  29 enum timer_source eal_timer_source = EAL_TIMER_HPET;
  30
  31 #ifdef RTE_LIBEAL_USE_HPET
  32
  33 #define DEV_HPET "/dev/hpet"
  34
  35 /* Maximum number of counters. */
  36 #define HPET_TIMER_NUM 3
  37
  38 /* General capabilities register */
  39 #define CLK_PERIOD_SHIFT     32 /* Clock period shift. */
  40 #define CLK_PERIOD_MASK      0xffffffff00000000ULL /* Clock period mask. */
  41
  42 /**
  43  * HPET timer registers. From the Intel IA-PC HPET (High Precision Event
  44  * Timers) Specification.
  45  */
  46 struct eal_hpet_regs {
  47         /* Memory-mapped, software visible registers */
  48         uint64_t capabilities;      /**< RO General Capabilities Register. */
  49         uint64_t reserved0;         /**< Reserved for future use. */
  50         uint64_t config;            /**< RW General Configuration Register. */
  51         uint64_t reserved1;         /**< Reserved for future use. */
  52         uint64_t isr;               /**< RW Clear General Interrupt Status. */
  53         uint64_t reserved2[25];     /**< Reserved for future use. */
  54         union {
  55                 uint64_t counter;   /**< RW Main Counter Value Register. */
  56                 struct {
  57                         uint32_t counter_l; /**< RW Main Counter Low. */
  58                         uint32_t counter_h; /**< RW Main Counter High. */
  59                 };
  60         };
  61         uint64_t reserved3;         /**< Reserved for future use. */
  62         struct {
  63                 uint64_t config;    /**< RW Timer Config and Capability Reg. */
  64                 uint64_t comp;      /**< RW Timer Comparator Value Register. */
  65                 uint64_t fsb;       /**< RW FSB Interrupt Route Register. */
  66                 uint64_t reserved4; /**< Reserved for future use. */
  67         } timers[HPET_TIMER_NUM]; /**< Set of HPET timers. */
  68 };
  69
  70 /* Mmap'd hpet registers */
  71 static volatile struct eal_hpet_regs *eal_hpet = NULL;
  72
  73 /* Period at which the HPET counter increments in
  74  * femtoseconds (10^-15 seconds). */
  75 static uint32_t eal_hpet_resolution_fs = 0;
  76
  77 /* Frequency of the HPET counter in Hz */
  78 static uint64_t eal_hpet_resolution_hz = 0;
  79
  80 /* Incremented 4 times during one 32bits hpet full count */
  81 static uint32_t eal_hpet_msb;
  82
  83 static pthread_t msb_inc_thread_id;
  84
  85 /*
  86  * This function runs on a specific thread to update a global variable
  87  * containing used to process MSB of the HPET (unfortunately, we need
  88  * this because hpet is 32 bits by default under linux).
  89  */
  90 static void *
  91 hpet_msb_inc(__attribute__((unused)) void *arg)
  92 {
  93         uint32_t t;
  94
  95         while (1) {
  96                 t = (eal_hpet->counter_l >> 30);
  97                 if (t != (eal_hpet_msb & 3))
  98                         eal_hpet_msb ++;
  99                 sleep(10);
 100         }
 101         return NULL;
 102 }
 103
 104 uint64_t
 105 rte_get_hpet_hz(void)
 106 {
 107         if(internal_config.no_hpet)
 108                 rte_panic("Error, HPET called, but no HPET present\n");
 109
 110         return eal_hpet_resolution_hz;
 111 }
 112
 113 uint64_t
 114 rte_get_hpet_cycles(void)
 115 {
 116         uint32_t t, msb;
 117         uint64_t ret;
 118
 119         if(internal_config.no_hpet)
 120                 rte_panic("Error, HPET called, but no HPET present\n");
 121
 122         t = eal_hpet->counter_l;
 123         msb = eal_hpet_msb;
 124         ret = (msb + 2 - (t >> 30)) / 4;
 125         ret <<= 32;
 126         ret += t;
 127         return ret;
 128 }
 129
 130 #endif
 131
 132 #ifdef RTE_LIBEAL_USE_HPET
 133 /*
 134  * Open and mmap /dev/hpet (high precision event timer) that will
 135  * provide our time reference.
 136  */
 137 int
 138 rte_eal_hpet_init(int make_default)
 139 {
 140         int fd, ret;
 141
 142         if (internal_config.no_hpet) {
 143                 RTE_LOG(NOTICE, EAL, "HPET is disabled\n");
 144                 return -1;
 145         }
 146
 147         fd = open(DEV_HPET, O_RDONLY);
 148         if (fd < 0) {
 149                 RTE_LOG(ERR, EAL, "ERROR: Cannot open "DEV_HPET": %s!\n",
 150                         strerror(errno));
 151                 internal_config.no_hpet = 1;
 152                 return -1;
 153         }
 154         eal_hpet = mmap(NULL, 1024, PROT_READ, MAP_SHARED, fd, 0);
 155         if (eal_hpet == MAP_FAILED) {
 156                 RTE_LOG(ERR, EAL, "ERROR: Cannot mmap "DEV_HPET"!\n"
 157                                 "Please enable CONFIG_HPET_MMAP in your kernel configuration "
 158                                 "to allow HPET support.\n"
 159                                 "To run without using HPET, set CONFIG_RTE_LIBEAL_USE_HPET=n "
 160                                 "in your build configuration or use '--no-hpet' EAL flag.\n");
 161                 close(fd);
 162                 internal_config.no_hpet = 1;
 163                 return -1;
 164         }
 165         close(fd);
 166
 167         eal_hpet_resolution_fs = (uint32_t)((eal_hpet->capabilities &
 168                                         CLK_PERIOD_MASK) >>
 169                                         CLK_PERIOD_SHIFT);
 170
 171         eal_hpet_resolution_hz = (1000ULL*1000ULL*1000ULL*1000ULL*1000ULL) /
 172                 (uint64_t)eal_hpet_resolution_fs;
 173
 174         RTE_LOG(INFO, EAL, "HPET frequency is ~%"PRIu64" kHz\n",
 175                         eal_hpet_resolution_hz/1000);
 176
 177         eal_hpet_msb = (eal_hpet->counter_l >> 30);
 178
 179         /* create a thread that will increment a global variable for
 180          * msb (hpet is 32 bits by default under linux) */
 181         ret = rte_ctrl_thread_create(&msb_inc_thread_id, "hpet-msb-inc", NULL,
 182                                      hpet_msb_inc, NULL);
 183         if (ret != 0) {
 184                 RTE_LOG(ERR, EAL, "ERROR: Cannot create HPET timer thread!\n");
 185                 internal_config.no_hpet = 1;
 186                 return -1;
 187         }
 188
 189         if (make_default)
 190                 eal_timer_source = EAL_TIMER_HPET;
 191         return 0;
 192 }
 193 #endif
 194
 195 static void
 196 check_tsc_flags(void)
 197 {
 198         char line[512];
 199         FILE *stream;
 200
 201         stream = fopen("/proc/cpuinfo", "r");
 202         if (!stream) {
 203                 RTE_LOG(WARNING, EAL, "WARNING: Unable to open /proc/cpuinfo\n");
 204                 return;
 205         }
 206
 207         while (fgets(line, sizeof line, stream)) {
 208                 char *constant_tsc;
 209                 char *nonstop_tsc;
 210
 211                 if (strncmp(line, "flags", 5) != 0)
 212                         continue;
 213
 214                 constant_tsc = strstr(line, "constant_tsc");
 215                 nonstop_tsc = strstr(line, "nonstop_tsc");
 216                 if (!constant_tsc || !nonstop_tsc)
 217                         RTE_LOG(WARNING, EAL,
 218                                 "WARNING: cpu flags "
 219                                 "constant_tsc=%s "
 220                                 "nonstop_tsc=%s "
 221                                 "-> using unreliable clock cycles !\n",
 222                                 constant_tsc ? "yes":"no",
 223                                 nonstop_tsc ? "yes":"no");
 224                 break;
 225         }
 226
 227         fclose(stream);
 228 }
 229
 230 uint64_t
 231 get_tsc_freq(void)
 232 {
 233 #ifdef CLOCK_MONOTONIC_RAW
 234 #define NS_PER_SEC 1E9
 235 #define CYC_PER_10MHZ 1E7
 236
 237         struct timespec sleeptime = {.tv_nsec = NS_PER_SEC / 10 }; /* 1/10 second */
 238
 239         struct timespec t_start, t_end;
 240         uint64_t tsc_hz;
 241
 242         if (clock_gettime(CLOCK_MONOTONIC_RAW, &t_start) == 0) {
 243                 uint64_t ns, end, start = rte_rdtsc();
 244                 nanosleep(&sleeptime,NULL);
 245                 clock_gettime(CLOCK_MONOTONIC_RAW, &t_end);
 246                 end = rte_rdtsc();
 247                 ns = ((t_end.tv_sec - t_start.tv_sec) * NS_PER_SEC);
 248                 ns += (t_end.tv_nsec - t_start.tv_nsec);
 249
 250                 double secs = (double)ns/NS_PER_SEC;
 251                 tsc_hz = (uint64_t)((end - start)/secs);
 252                 /* Round up to 10Mhz. 1E7 ~ 10Mhz */
 253                 return RTE_ALIGN_MUL_NEAR(tsc_hz, CYC_PER_10MHZ);
 254         }
 255 #endif
 256         return 0;
 257 }
 258
 259 int
 260 rte_eal_timer_init(void)
 261 {
 262
 263         eal_timer_source = EAL_TIMER_TSC;
 264
 265         set_tsc_freq();
 266         check_tsc_flags();
 267         return 0;
 268 }