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 #if defined(HAVE_PTHREAD) && !defined(ANDROID) && !defined(__APPLE__)
  40 #define HAVE_PTHREAD_SETAFFINITY
  41 #endif
  42
  43 static inline thrd_t u_thread_create(int (*routine)(void *), void *param)
  44 {
  45    thrd_t thread;
  46 #ifdef HAVE_PTHREAD
  47    sigset_t saved_set, new_set;
  48    int ret;
  49
  50    sigfillset(&new_set);
  51    pthread_sigmask(SIG_SETMASK, &new_set, &saved_set);
  52    ret = thrd_create( &thread, routine, param );
  53    pthread_sigmask(SIG_SETMASK, &saved_set, NULL);
  54 #else
  55    int ret;
  56    ret = thrd_create( &thread, routine, param );
  57 #endif
  58    if (ret)
  59       return 0;
  60
  61    return thread;
  62 }
  63
  64 static inline void u_thread_setname( const char *name )
  65 {
  66 #if defined(HAVE_PTHREAD)
  67 #  if defined(__GNU_LIBRARY__) && defined(__GLIBC__) && defined(__GLIBC_MINOR__) && \
  68       (__GLIBC__ >= 3 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 12)) && \
  69       defined(__linux__)
  70    pthread_setname_np(pthread_self(), name);
  71 #  endif
  72 #endif
  73    (void)name;
  74 }
  75
  76 /**
  77  * An AMD Zen CPU consists of multiple modules where each module has its own L3
  78  * cache. Inter-thread communication such as locks and atomics between modules
  79  * is very expensive. It's desirable to pin a group of closely cooperating
  80  * threads to one group of cores sharing L3.
  81  *
  82  * \param thread        thread
  83  * \param L3_index      index of the L3 cache
  84  * \param cores_per_L3  number of CPU cores shared by one L3
  85  */
  86 static inline void
  87 util_pin_thread_to_L3(thrd_t thread, unsigned L3_index, unsigned cores_per_L3)
  88 {
  89 #if defined(HAVE_PTHREAD_SETAFFINITY)
  90    cpu_set_t cpuset;
  91
  92    CPU_ZERO(&cpuset);
  93    for (unsigned i = 0; i < cores_per_L3; i++)
  94       CPU_SET(L3_index * cores_per_L3 + i, &cpuset);
  95    pthread_setaffinity_np(thread, sizeof(cpuset), &cpuset);
  96 #endif
  97 }
  98
  99 /**
 100  * Return the index of L3 that the thread is pinned to. If the thread is
 101  * pinned to multiple L3 caches, return -1.
 102  *
 103  * \param thread        thread
 104  * \param cores_per_L3  number of CPU cores shared by one L3
 105  */
 106 static inline int
 107 util_get_L3_for_pinned_thread(thrd_t thread, unsigned cores_per_L3)
 108 {
 109 #if defined(HAVE_PTHREAD_SETAFFINITY)
 110    cpu_set_t cpuset;
 111
 112    if (pthread_getaffinity_np(thread, sizeof(cpuset), &cpuset) == 0) {
 113       int L3_index = -1;
 114
 115       for (unsigned i = 0; i < CPU_SETSIZE; i++) {
 116          if (CPU_ISSET(i, &cpuset)) {
 117             int x = i / cores_per_L3;
 118
 119             if (L3_index != x) {
 120                if (L3_index == -1)
 121                   L3_index = x;
 122                else
 123                   return -1; /* multiple L3s are set */
 124             }
 125          }
 126       }
 127       return L3_index;
 128    }
 129 #endif
 130    return -1;
 131 }
 132
 133 /*
 134  * Thread statistics.
 135  */
 136
 137 /* Return the time of a thread's CPU time clock. */
 138 static inline int64_t
 139 u_thread_get_time_nano(thrd_t thread)
 140 {
 141 #if defined(__linux__) && defined(HAVE_PTHREAD)
 142    struct timespec ts;
 143    clockid_t cid;
 144
 145    pthread_getcpuclockid(thread, &cid);
 146    clock_gettime(cid, &ts);
 147    return (int64_t)ts.tv_sec * 1000000000 + ts.tv_nsec;
 148 #else
 149    return 0;
 150 #endif
 151 }
 152
 153 static inline bool u_thread_is_self(thrd_t thread)
 154 {
 155 #if defined(HAVE_PTHREAD)
 156 #  if defined(__GNU_LIBRARY__) && defined(__GLIBC__) && defined(__GLIBC_MINOR__) && \
 157       (__GLIBC__ >= 3 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 12))
 158    return pthread_equal(pthread_self(), thread);
 159 #  endif
 160 #endif
 161    return false;
 162 }
 163
 164 /*
 165  * util_barrier
 166  */
 167
 168 #if defined(HAVE_PTHREAD) && !defined(__APPLE__)
 169
 170 typedef pthread_barrier_t util_barrier;
 171
 172 static inline void util_barrier_init(util_barrier *barrier, unsigned count)
 173 {
 174    pthread_barrier_init(barrier, NULL, count);
 175 }
 176
 177 static inline void util_barrier_destroy(util_barrier *barrier)
 178 {
 179    pthread_barrier_destroy(barrier);
 180 }
 181
 182 static inline void util_barrier_wait(util_barrier *barrier)
 183 {
 184    pthread_barrier_wait(barrier);
 185 }
 186
 187
 188 #else /* If the OS doesn't have its own, implement barriers using a mutex and a condvar */
 189
 190 typedef struct {
 191    unsigned count;
 192    unsigned waiters;
 193    uint64_t sequence;
 194    mtx_t mutex;
 195    cnd_t condvar;
 196 } util_barrier;
 197
 198 static inline void util_barrier_init(util_barrier *barrier, unsigned count)
 199 {
 200    barrier->count = count;
 201    barrier->waiters = 0;
 202    barrier->sequence = 0;
 203    (void) mtx_init(&barrier->mutex, mtx_plain);
 204    cnd_init(&barrier->condvar);
 205 }
 206
 207 static inline void util_barrier_destroy(util_barrier *barrier)
 208 {
 209    assert(barrier->waiters == 0);
 210    mtx_destroy(&barrier->mutex);
 211    cnd_destroy(&barrier->condvar);
 212 }
 213
 214 static inline void util_barrier_wait(util_barrier *barrier)
 215 {
 216    mtx_lock(&barrier->mutex);
 217
 218    assert(barrier->waiters < barrier->count);
 219    barrier->waiters++;
 220
 221    if (barrier->waiters < barrier->count) {
 222       uint64_t sequence = barrier->sequence;
 223
 224       do {
 225          cnd_wait(&barrier->condvar, &barrier->mutex);
 226       } while (sequence == barrier->sequence);
 227    } else {
 228       barrier->waiters = 0;
 229       barrier->sequence++;
 230       cnd_broadcast(&barrier->condvar);
 231    }
 232
 233    mtx_unlock(&barrier->mutex);
 234 }
 235
 236 #endif
 237
 238 #endif /* U_THREAD_H_ */