ceph/src/seastar/dpdk/examples/performance-thread/pthread_shim/main.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2015 Intel Corporation
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <stdint.h>
   8 #include <inttypes.h>
   9 #include <sys/types.h>
  10 #include <string.h>
  11 #include <sys/queue.h>
  12 #include <stdarg.h>
  13 #include <errno.h>
  14 #include <getopt.h>
  15 #include <unistd.h>
  16 #include <sched.h>
  17 #include <pthread.h>
  18
  19 #include <rte_common.h>
  20 #include <rte_lcore.h>
  21 #include <rte_per_lcore.h>
  22 #include <rte_timer.h>
  23
  24 #include "lthread_api.h"
  25 #include "lthread_diag_api.h"
  26 #include "pthread_shim.h"
  27
  28 #define DEBUG_APP 0
  29 #define HELLOW_WORLD_MAX_LTHREADS 10
  30
  31 #ifndef __GLIBC__ /* sched_getcpu() is glibc-specific */
  32 #define sched_getcpu() rte_lcore_id()
  33 #endif
  34
  35 __thread int print_count;
  36 __thread pthread_mutex_t print_lock;
  37
  38 __thread pthread_mutex_t exit_lock;
  39 __thread pthread_cond_t exit_cond;
  40
  41 /*
  42  * A simple thread that demonstrates use of a mutex, a condition
  43  * variable, thread local storage, explicit yield, and thread exit.
  44  *
  45  * The thread uses a mutex to protect a shared counter which is incremented
  46  * and then it waits on condition variable before exiting.
  47  *
  48  * The thread argument is stored in and retrieved from TLS, using
  49  * the pthread key create, get and set specific APIs.
  50  *
  51  * The thread yields while holding the mutex, to provide opportunity
  52  * for other threads to contend.
  53  *
  54  * All of the pthread API functions used by this thread are actually
  55  * resolved to corresponding lthread functions by the pthread shim
  56  * implemented in pthread_shim.c
  57  */
  58 void *helloworld_pthread(void *arg);
  59 void *helloworld_pthread(void *arg)
  60 {
  61         pthread_key_t key;
  62
  63         /* create a key for TLS */
  64         pthread_key_create(&key, NULL);
  65
  66         /* store the arg in TLS */
  67         pthread_setspecific(key, arg);
  68
  69         /* grab lock and increment shared counter */
  70         pthread_mutex_lock(&print_lock);
  71         print_count++;
  72
  73         /* yield thread to give opportunity for lock contention */
  74         pthread_yield();
  75
  76         /* retrieve arg from TLS */
  77         uint64_t thread_no = (uint64_t) pthread_getspecific(key);
  78
  79         printf("Hello - lcore = %d count = %d thread_no = %d thread_id = %p\n",
  80                         sched_getcpu(),
  81                         print_count,
  82                         (int) thread_no,
  83                         (void *)pthread_self());
  84
  85         /* release the lock */
  86         pthread_mutex_unlock(&print_lock);
  87
  88         /*
  89          * wait on condition variable
  90          * before exiting
  91          */
  92         pthread_mutex_lock(&exit_lock);
  93         pthread_cond_wait(&exit_cond, &exit_lock);
  94         pthread_mutex_unlock(&exit_lock);
  95
  96         /* exit */
  97         pthread_exit((void *) thread_no);
  98 }
  99
 100
 101 /*
 102  * This is the initial thread
 103  *
 104  * It demonstrates pthread, mutex and condition variable creation,
 105  * broadcast and pthread join APIs.
 106  *
 107  * This initial thread must always start life as an lthread.
 108  *
 109  * This thread creates many more threads then waits a short time
 110  * before signalling them to exit using a broadcast.
 111  *
 112  * All of the pthread API functions used by this thread are actually
 113  * resolved to corresponding lthread functions by the pthread shim
 114  * implemented in pthread_shim.c
 115  *
 116  * After all threads have finished the lthread scheduler is shutdown
 117  * and normal pthread operation is restored
 118  */
 119 __thread pthread_t tid[HELLOW_WORLD_MAX_LTHREADS];
 120
 121 static void *initial_lthread(void *args __attribute__((unused)))
 122 {
 123         int lcore = (int) rte_lcore_id();
 124         /*
 125          *
 126          * We can now enable pthread API override
 127          * and start to use the pthread APIs
 128          */
 129         pthread_override_set(1);
 130
 131         uint64_t i;
 132         int ret;
 133
 134         /* initialize mutex for shared counter */
 135         print_count = 0;
 136         pthread_mutex_init(&print_lock, NULL);
 137
 138         /* initialize mutex and condition variable controlling thread exit */
 139         pthread_mutex_init(&exit_lock, NULL);
 140         pthread_cond_init(&exit_cond, NULL);
 141
 142         /* spawn a number of threads */
 143         for (i = 0; i < HELLOW_WORLD_MAX_LTHREADS; i++) {
 144
 145                 /*
 146                  * Not strictly necessary but
 147                  * for the sake of this example
 148                  * use an attribute to pass the desired lcore
 149                  */
 150                 pthread_attr_t attr;
 151                 rte_cpuset_t cpuset;
 152
 153                 CPU_ZERO(&cpuset);
 154                 CPU_SET(lcore, &cpuset);
 155                 pthread_attr_init(&attr);
 156                 pthread_attr_setaffinity_np(&attr, sizeof(rte_cpuset_t), &cpuset);
 157
 158                 /* create the thread */
 159                 ret = pthread_create(&tid[i], &attr,
 160                                 helloworld_pthread, (void *) i);
 161                 if (ret != 0)
 162                         rte_exit(EXIT_FAILURE, "Cannot create helloworld thread\n");
 163         }
 164
 165         /* wait for 1s to allow threads
 166          * to block on the condition variable
 167          * N.B. nanosleep() is resolved to lthread_sleep()
 168          * by the shim.
 169          */
 170         struct timespec time;
 171
 172         time.tv_sec = 1;
 173         time.tv_nsec = 0;
 174         nanosleep(&time, NULL);
 175
 176         /* wake up all the threads */
 177         pthread_cond_broadcast(&exit_cond);
 178
 179         /* wait for them to finish */
 180         for (i = 0; i < HELLOW_WORLD_MAX_LTHREADS; i++) {
 181
 182                 uint64_t thread_no;
 183
 184                 pthread_join(tid[i], (void *) &thread_no);
 185                 if (thread_no != i)
 186                         printf("error on thread exit\n");
 187         }
 188
 189         pthread_cond_destroy(&exit_cond);
 190         pthread_mutex_destroy(&print_lock);
 191         pthread_mutex_destroy(&exit_lock);
 192
 193         /* shutdown the lthread scheduler */
 194         lthread_scheduler_shutdown(rte_lcore_id());
 195         lthread_detach();
 196         return NULL;
 197 }
 198
 199
 200
 201 /* This thread creates a single initial lthread
 202  * and then runs the scheduler
 203  * An instance of this thread is created on each thread
 204  * in the core mask
 205  */
 206 static int
 207 lthread_scheduler(void *args __attribute__((unused)))
 208 {
 209         /* create initial thread  */
 210         struct lthread *lt;
 211
 212         lthread_create(&lt, -1, initial_lthread, (void *) NULL);
 213
 214         /* run the lthread scheduler */
 215         lthread_run();
 216
 217         /* restore genuine pthread operation */
 218         pthread_override_set(0);
 219         return 0;
 220 }
 221
 222 int main(int argc, char **argv)
 223 {
 224         int num_sched = 0;
 225
 226         /* basic DPDK initialization is all that is necessary to run lthreads*/
 227         int ret = rte_eal_init(argc, argv);
 228
 229         if (ret < 0)
 230                 rte_exit(EXIT_FAILURE, "Invalid EAL parameters\n");
 231
 232         /* enable timer subsystem */
 233         rte_timer_subsystem_init();
 234
 235 #if DEBUG_APP
 236         lthread_diagnostic_set_mask(LT_DIAG_ALL);
 237 #endif
 238
 239         /* create a scheduler on every core in the core mask
 240          * and launch an initial lthread that will spawn many more.
 241          */
 242         unsigned lcore_id;
 243
 244         for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
 245                 if (rte_lcore_is_enabled(lcore_id))
 246                         num_sched++;
 247         }
 248
 249         /* set the number of schedulers, this forces all schedulers synchronize
 250          * before entering their main loop
 251          */
 252         lthread_num_schedulers_set(num_sched);
 253
 254         /* launch all threads */
 255         rte_eal_mp_remote_launch(lthread_scheduler, (void *)NULL, CALL_MASTER);
 256
 257         /* wait for threads to stop */
 258         RTE_LCORE_FOREACH_SLAVE(lcore_id) {
 259                 rte_eal_wait_lcore(lcore_id);
 260         }
 261         return 0;
 262 }