src/util/u_thread.h

   1 /**************************************************************************
   2  *
   3  * Copyright 1999-2006 Brian Paul
   4  * Copyright 2008 VMware, Inc.
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  *
  25  **************************************************************************/
  26
  27 #ifndef U_THREAD_H_
  28 #define U_THREAD_H_
  29
  30 #include <stdint.h>
  31 #include <stdbool.h>
  32
  33 #include "c11/threads.h"
  34
  35 #ifdef HAVE_PTHREAD
  36 #include <signal.h>
  37 #endif
  38
  39 static inline thrd_t u_thread_create(int (*routine)(void *), void *param)
  40 {
  41    thrd_t thread;
  42 #ifdef HAVE_PTHREAD
  43    sigset_t saved_set, new_set;
  44    int ret;
  45
  46    sigfillset(&new_set);
  47    pthread_sigmask(SIG_SETMASK, &new_set, &saved_set);
  48    ret = thrd_create( &thread, routine, param );
  49    pthread_sigmask(SIG_SETMASK, &saved_set, NULL);
  50 #else
  51    int ret;
  52    ret = thrd_create( &thread, routine, param );
  53 #endif
  54    if (ret)
  55       return 0;
  56
  57    return thread;
  58 }
  59
  60 static inline void u_thread_setname( const char *name )
  61 {
  62 #if defined(HAVE_PTHREAD)
  63 #  if defined(__GNU_LIBRARY__) && defined(__GLIBC__) && defined(__GLIBC_MINOR__) && \
  64       (__GLIBC__ >= 3 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 12)) && \
  65       defined(__linux__)
  66    pthread_setname_np(pthread_self(), name);
  67 #  endif
  68 #endif
  69    (void)name;
  70 }
  71
  72 /**
  73  * An AMD Zen CPU consists of multiple modules where each module has its own L3
  74  * cache. Inter-thread communication such as locks and atomics between modules
  75  * is very expensive. It's desirable to pin a group of closely cooperating
  76  * threads to one group of cores sharing L3.
  77  *
  78  * \param thread        thread
  79  * \param L3_index      index of the L3 cache
  80  * \param cores_per_L3  number of CPU cores shared by one L3
  81  */
  82 static inline void
  83 util_pin_thread_to_L3(thrd_t thread, unsigned L3_index, unsigned cores_per_L3)
  84 {
  85 #if defined(HAVE_PTHREAD_SETAFFINITY)
  86    cpu_set_t cpuset;
  87
  88    CPU_ZERO(&cpuset);
  89    for (unsigned i = 0; i < cores_per_L3; i++)
  90       CPU_SET(L3_index * cores_per_L3 + i, &cpuset);
  91    pthread_setaffinity_np(thread, sizeof(cpuset), &cpuset);
  92 #endif
  93 }
  94
  95 /**
  96  * Return the index of L3 that the thread is pinned to. If the thread is
  97  * pinned to multiple L3 caches, return -1.
  98  *
  99  * \param thread        thread
 100  * \param cores_per_L3  number of CPU cores shared by one L3
 101  */
 102 static inline int
 103 util_get_L3_for_pinned_thread(thrd_t thread, unsigned cores_per_L3)
 104 {
 105 #if defined(HAVE_PTHREAD_SETAFFINITY)
 106    cpu_set_t cpuset;
 107
 108    if (pthread_getaffinity_np(thread, sizeof(cpuset), &cpuset) == 0) {
 109       int L3_index = -1;
 110
 111       for (unsigned i = 0; i < CPU_SETSIZE; i++) {
 112          if (CPU_ISSET(i, &cpuset)) {
 113             int x = i / cores_per_L3;
 114
 115             if (L3_index != x) {
 116                if (L3_index == -1)
 117                   L3_index = x;
 118                else
 119                   return -1; /* multiple L3s are set */
 120             }
 121          }
 122       }
 123       return L3_index;
 124    }
 125 #endif
 126    return -1;
 127 }
 128
 129 /*
 130  * Thread statistics.
 131  */
 132
 133 /* Return the time of a thread's CPU time clock. */
 134 static inline int64_t
 135 u_thread_get_time_nano(thrd_t thread)
 136 {
 137 #if defined(__linux__) && defined(HAVE_PTHREAD)
 138    struct timespec ts;
 139    clockid_t cid;
 140
 141    pthread_getcpuclockid(thread, &cid);
 142    clock_gettime(cid, &ts);
 143    return (int64_t)ts.tv_sec * 1000000000 + ts.tv_nsec;
 144 #else
 145    return 0;
 146 #endif
 147 }
 148
 149 static inline bool u_thread_is_self(thrd_t thread)
 150 {
 151 #if defined(HAVE_PTHREAD)
 152 #  if defined(__GNU_LIBRARY__) && defined(__GLIBC__) && defined(__GLIBC_MINOR__) && \
 153       (__GLIBC__ >= 3 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 12))
 154    return pthread_equal(pthread_self(), thread);
 155 #  endif
 156 #endif
 157    return false;
 158 }
 159
 160 /*
 161  * util_barrier
 162  */
 163
 164 #if defined(HAVE_PTHREAD) && !defined(__APPLE__)
 165
 166 typedef pthread_barrier_t util_barrier;
 167
 168 static inline void util_barrier_init(util_barrier *barrier, unsigned count)
 169 {
 170    pthread_barrier_init(barrier, NULL, count);
 171 }
 172
 173 static inline void util_barrier_destroy(util_barrier *barrier)
 174 {
 175    pthread_barrier_destroy(barrier);
 176 }
 177
 178 static inline void util_barrier_wait(util_barrier *barrier)
 179 {
 180    pthread_barrier_wait(barrier);
 181 }
 182
 183
 184 #else /* If the OS doesn't have its own, implement barriers using a mutex and a condvar */
 185
 186 typedef struct {
 187    unsigned count;
 188    unsigned waiters;
 189    uint64_t sequence;
 190    mtx_t mutex;
 191    cnd_t condvar;
 192 } util_barrier;
 193
 194 static inline void util_barrier_init(util_barrier *barrier, unsigned count)
 195 {
 196    barrier->count = count;
 197    barrier->waiters = 0;
 198    barrier->sequence = 0;
 199    (void) mtx_init(&barrier->mutex, mtx_plain);
 200    cnd_init(&barrier->condvar);
 201 }
 202
 203 static inline void util_barrier_destroy(util_barrier *barrier)
 204 {
 205    assert(barrier->waiters == 0);
 206    mtx_destroy(&barrier->mutex);
 207    cnd_destroy(&barrier->condvar);
 208 }
 209
 210 static inline void util_barrier_wait(util_barrier *barrier)
 211 {
 212    mtx_lock(&barrier->mutex);
 213
 214    assert(barrier->waiters < barrier->count);
 215    barrier->waiters++;
 216
 217    if (barrier->waiters < barrier->count) {
 218       uint64_t sequence = barrier->sequence;
 219
 220       do {
 221          cnd_wait(&barrier->condvar, &barrier->mutex);
 222       } while (sequence == barrier->sequence);
 223    } else {
 224       barrier->waiters = 0;
 225       barrier->sequence++;
 226       cnd_broadcast(&barrier->condvar);
 227    }
 228
 229    mtx_unlock(&barrier->mutex);
 230 }
 231
 232 #endif
 233
 234 #endif /* U_THREAD_H_ */