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    sigdelset(&new_set, SIGSYS);
  48    pthread_sigmask(SIG_BLOCK, &new_set, &saved_set);
  49    ret = thrd_create( &thread, routine, param );
  50    pthread_sigmask(SIG_SETMASK, &saved_set, NULL);
  51 #else
  52    int ret;
  53    ret = thrd_create( &thread, routine, param );
  54 #endif
  55    if (ret)
  56       return 0;
  57
  58    return thread;
  59 }
  60
  61 static inline void u_thread_setname( const char *name )
  62 {
  63 #if defined(HAVE_PTHREAD)
  64    pthread_setname_np(pthread_self(), name);
  65 #endif
  66    (void)name;
  67 }
  68
  69 /**
  70  * An AMD Zen CPU consists of multiple modules where each module has its own L3
  71  * cache. Inter-thread communication such as locks and atomics between modules
  72  * is very expensive. It's desirable to pin a group of closely cooperating
  73  * threads to one group of cores sharing L3.
  74  *
  75  * \param thread        thread
  76  * \param L3_index      index of the L3 cache
  77  * \param cores_per_L3  number of CPU cores shared by one L3
  78  */
  79 static inline void
  80 util_pin_thread_to_L3(thrd_t thread, unsigned L3_index, unsigned cores_per_L3)
  81 {
  82 #if defined(HAVE_PTHREAD_SETAFFINITY)
  83    cpu_set_t cpuset;
  84
  85    CPU_ZERO(&cpuset);
  86    for (unsigned i = 0; i < cores_per_L3; i++)
  87       CPU_SET(L3_index * cores_per_L3 + i, &cpuset);
  88    pthread_setaffinity_np(thread, sizeof(cpuset), &cpuset);
  89 #endif
  90 }
  91
  92 /**
  93  * Return the index of L3 that the thread is pinned to. If the thread is
  94  * pinned to multiple L3 caches, return -1.
  95  *
  96  * \param thread        thread
  97  * \param cores_per_L3  number of CPU cores shared by one L3
  98  */
  99 static inline int
 100 util_get_L3_for_pinned_thread(thrd_t thread, unsigned cores_per_L3)
 101 {
 102 #if defined(HAVE_PTHREAD_SETAFFINITY)
 103    cpu_set_t cpuset;
 104
 105    if (pthread_getaffinity_np(thread, sizeof(cpuset), &cpuset) == 0) {
 106       int L3_index = -1;
 107
 108       for (unsigned i = 0; i < CPU_SETSIZE; i++) {
 109          if (CPU_ISSET(i, &cpuset)) {
 110             int x = i / cores_per_L3;
 111
 112             if (L3_index != x) {
 113                if (L3_index == -1)
 114                   L3_index = x;
 115                else
 116                   return -1; /* multiple L3s are set */
 117             }
 118          }
 119       }
 120       return L3_index;
 121    }
 122 #endif
 123    return -1;
 124 }
 125
 126 /*
 127  * Thread statistics.
 128  */
 129
 130 /* Return the time of a thread's CPU time clock. */
 131 static inline int64_t
 132 u_thread_get_time_nano(thrd_t thread)
 133 {
 134 #if defined(__linux__) && defined(HAVE_PTHREAD)
 135    struct timespec ts;
 136    clockid_t cid;
 137
 138    pthread_getcpuclockid(thread, &cid);
 139    clock_gettime(cid, &ts);
 140    return (int64_t)ts.tv_sec * 1000000000 + ts.tv_nsec;
 141 #else
 142    return 0;
 143 #endif
 144 }
 145
 146 static inline bool u_thread_is_self(thrd_t thread)
 147 {
 148 #if defined(HAVE_PTHREAD)
 149    return pthread_equal(pthread_self(), thread);
 150 #endif
 151    return false;
 152 }
 153
 154 /*
 155  * util_barrier
 156  */
 157
 158 #if defined(HAVE_PTHREAD) && !defined(__APPLE__)
 159
 160 typedef pthread_barrier_t util_barrier;
 161
 162 static inline void util_barrier_init(util_barrier *barrier, unsigned count)
 163 {
 164    pthread_barrier_init(barrier, NULL, count);
 165 }
 166
 167 static inline void util_barrier_destroy(util_barrier *barrier)
 168 {
 169    pthread_barrier_destroy(barrier);
 170 }
 171
 172 static inline void util_barrier_wait(util_barrier *barrier)
 173 {
 174    pthread_barrier_wait(barrier);
 175 }
 176
 177
 178 #else /* If the OS doesn't have its own, implement barriers using a mutex and a condvar */
 179
 180 typedef struct {
 181    unsigned count;
 182    unsigned waiters;
 183    uint64_t sequence;
 184    mtx_t mutex;
 185    cnd_t condvar;
 186 } util_barrier;
 187
 188 static inline void util_barrier_init(util_barrier *barrier, unsigned count)
 189 {
 190    barrier->count = count;
 191    barrier->waiters = 0;
 192    barrier->sequence = 0;
 193    (void) mtx_init(&barrier->mutex, mtx_plain);
 194    cnd_init(&barrier->condvar);
 195 }
 196
 197 static inline void util_barrier_destroy(util_barrier *barrier)
 198 {
 199    assert(barrier->waiters == 0);
 200    mtx_destroy(&barrier->mutex);
 201    cnd_destroy(&barrier->condvar);
 202 }
 203
 204 static inline void util_barrier_wait(util_barrier *barrier)
 205 {
 206    mtx_lock(&barrier->mutex);
 207
 208    assert(barrier->waiters < barrier->count);
 209    barrier->waiters++;
 210
 211    if (barrier->waiters < barrier->count) {
 212       uint64_t sequence = barrier->sequence;
 213
 214       do {
 215          cnd_wait(&barrier->condvar, &barrier->mutex);
 216       } while (sequence == barrier->sequence);
 217    } else {
 218       barrier->waiters = 0;
 219       barrier->sequence++;
 220       cnd_broadcast(&barrier->condvar);
 221    }
 222
 223    mtx_unlock(&barrier->mutex);
 224 }
 225
 226 #endif
 227
 228 #endif /* U_THREAD_H_ */