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