Fix for threadpool abort function

Fixed an issue where if threadpool was aborted when some threads were in a running
state the threadpool would never exit. This was due to the fact that the thread
terminate task (func == NULL && args == NULL) could have been pushed to queues which
were inactive. This change adds a uint64_t mask of threads that have already exited
so whenever the terminate task is sent to another queue, it is ensured that the queue
used will wake up at least one tpool worker.

Also added pushTpool_mask which allows to specify a subset of threads to push the task
to but its only used internally.

Also added in this commit: A way to allocate thread-safe storage for thread pool
workers via get_tpool_worker_index. This index is unique to the thread pool worker
within one threadpool and can be used to access arrays in a thread-safe manner.

An example of such use was added in a testcase that was added which compares delay
between actors and threadpool workers.

common/utils/CMakeLists.txt

@@ -23,3 +23,6 @@ endif()
 add_subdirectory(barrier)
 add_subdirectory(actor)
 add_subdirectory(shm_iq_channel)
+if (ENABLE_TESTS)
+  add_subdirectory(tests)
+endif()

common/utils/tests/CMakeLists.txt

+add_executable(test_tpool_vs_actors test_tpool_vs_actors.c)
+target_link_libraries(test_tpool_vs_actors PRIVATE thread-pool pthread LOG minimal_lib actor)

common/utils/tests/test_tpool_vs_actors.c

+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+#include "actor.h"
+#include "thread-pool.h"
+#include "task.h"
+#include "log.h"
+#include <time.h>
+
+#define NUM_THREADS 10
+#define NUM_JOBS 200000
+
+typedef struct {
+  struct timespec ts;
+  int actor_index;
+} actor_task_t;
+
+long long delay_table[NUM_THREADS] = {0};
+
+void calculate_delay(struct timespec* send_ts, int thread_index)
+{
+  struct timespec ts;
+  clock_gettime(CLOCK_MONOTONIC, &ts);
+  long long recv_time = ts.tv_sec * 1000000000LL + ts.tv_nsec;
+  long long send_time = send_ts->tv_sec * 1000000000LL + send_ts->tv_nsec;
+  long long delay = recv_time - send_time;
+  delay_table[thread_index] += delay;
+}
+
+void tpool_function(void* args)
+{
+  int worker_id = get_tpool_worker_index();
+  calculate_delay((struct timespec*)args, worker_id);
+  free(args);
+}
+
+void actor_function(void* args)
+{
+  actor_task_t* actor_args = (actor_task_t*)args;
+  calculate_delay(&actor_args->ts, actor_args->actor_index);
+}
+
+int main()
+{
+  logInit();
+  tpool_t pool;
+  char params[NUM_THREADS * 4];
+  memset(params, 0, sizeof(params));
+  for (int i = 0; i < NUM_THREADS; i++) {
+    char buf[4];
+    snprintf(buf, sizeof(buf), "%d,", -1);
+    strcat(params, buf);
+  }
+
+  initTpool(params, &pool, true);
+
+  // Example task
+  task_t task;
+  task.func = tpool_function;
+  task.args = NULL;
+
+  // Push tasks to the thread pool
+  for (int i = 0; i < NUM_JOBS; i++) {
+    struct timespec* ts = malloc(sizeof(struct timespec));
+    clock_gettime(CLOCK_MONOTONIC, ts);
+    task.args = ts;
+    pushTpool(&pool, task);
+  }
+
+  // Abort the thread pool
+  abortTpool(&pool);
+
+  long long sum_delay = 0;
+  for (int i = 0; i < NUM_THREADS; i++) {
+    sum_delay += delay_table[i];
+  }
+  float average_delay = sum_delay / (NUM_JOBS * 1.0f);
+  printf("Average task delay on tpool: %.2f ns\n", average_delay);
+
+
+  memset(delay_table, 0, sizeof(delay_table));
+
+  Actor_t actors[NUM_THREADS];
+  for (int i = 0; i < NUM_THREADS; i++) {
+    init_actor(&actors[i], "example_actor", -1);
+  }
+
+  // Push tasks to the actors
+  for (int i = 0; i < NUM_JOBS; i++) {
+    notifiedFIFO_elt_t* task = newNotifiedFIFO_elt(sizeof(actor_task_t), 0, NULL, actor_function);
+    actor_task_t* arg_ts = (actor_task_t*)NotifiedFifoData(task);
+    arg_ts->actor_index = i % NUM_THREADS;
+    clock_gettime(CLOCK_MONOTONIC, &arg_ts->ts);
+    pushNotifiedFIFO(&actors[i % NUM_THREADS].fifo, task);
+  }
+
+  for (int i = 0; i < NUM_THREADS; i++) {
+    shutdown_actor(&actors[i]);
+  }
+
+  sum_delay = 0;
+  for (int i = 0; i < NUM_THREADS; i++) {
+    sum_delay += delay_table[i];
+  }
+  average_delay = sum_delay / (NUM_JOBS * 1.0f);
+  printf("Average task delay on actors: %.2f ns\n", average_delay);
+  return 0;
+}
\ No newline at end of file

common/utils/threadPool/thread-pool.c

@@ -55,12 +55,47 @@ void pushTpool(tpool_t* tpool, task_t task)
   push_not_q(&q_arr[index % len_thr], task);
 }
 
+// Same as above, but avoid certain tpool workers based on the mask
+void pushTpool_mask(tpool_t* tpool, task_t task, uint64_t mask)
+{
+  DevAssert(tpool != NULL);
+  if (tpool->len_thr == 0) {
+    task.func(task.args);
+    return;
+  }
+
+  size_t index = tpool->index++;
+  size_t const len_thr = tpool->len_thr;
+
+  not_q_t* q_arr = (not_q_t*)tpool->q_arr;
+
+  for (size_t i = 0; i < len_thr; ++i) {
+    int index = (i + tpool->index) % len_thr;
+    if ((1UL << index) & mask)
+      continue;
+    if (try_push_not_q(&q_arr[index], task)) {
+      return;
+    }
+  }
+
+  while ((1ULL << (index % len_thr)) & mask)
+    index++;
+  push_not_q(&q_arr[index % len_thr], task);
+}
+
+__thread int tpool_worker_index = -1;
+int get_tpool_worker_index(void)
+{
+  return tpool_worker_index;
+}
+
 static void* worker_thread(void* arg)
 {
   DevAssert(arg != NULL);
 
   task_thread_args_t* args = (task_thread_args_t*)arg;
   int const idx = args->idx;
+  tpool_worker_index = idx;
   tpool_t* tpool = args->tpool;
 
   uint32_t const len = tpool->len_thr;
@@ -87,7 +122,10 @@ static void* worker_thread(void* arg)
     }
 
     if (ret.t.func == NULL && ret.t.args == NULL) {
-      pushTpool(tpool, (task_t){.args = NULL, .func = NULL});
+      tpool->dead_mask |= 1ULL << idx;
+      if (__builtin_popcountll(tpool->dead_mask) == tpool->len_thr)
+        break;
+      pushTpool_mask(tpool, (task_t){.args = NULL, .func = NULL}, tpool->dead_mask);
       break;
     }
     ret.t.func(ret.t.args);

common/utils/threadPool/thread-pool.h

@@ -50,6 +50,7 @@ typedef struct {
   void* q_arr;
 
   pthread_barrier_t barrier;
+  _Atomic(uint64_t) dead_mask;
 } tpool_t;
 
 /// @brief Push job to threadpool. May run task inline in case there are no worker threads
@@ -82,4 +83,8 @@ void initFloatingCoresTpool(int nbThreads,tpool_t *pool, bool performanceMeas, c
 
 /// Convenience macro
 #define  initTpool(PARAMPTR,TPOOLPTR, MEASURFLAG) initNamedTpool(PARAMPTR,TPOOLPTR, MEASURFLAG, NULL)
+
+/// Returns the index of the worker thread in the thread pool
+/// @return index of the worker thread in a thread pool or -1 if not called from a thread pool worker thread
+int get_tpool_worker_index(void);
 #endif