O-RAN 7.2: set CPU affinity for ru_thread explicitly

Force the CPU affinity for ru_thread explicitly to ru_thread_core. It is
already done via threadCreate(), but force again as per change request.

Delete commented 7.2 code that did the equivalent. We cannot set it in
the driver, as we don't have access to variable ru->ru_thread_core.

Closes: #732 (suggestion 2)
Suggested-by: Andrew Sergeev <andrew.sergeev@adtran.com>

executables/nr-ru.c

@@ -1204,6 +1204,18 @@ void *ru_thread( void *param ) {
         malloc_IF4p5_buffer(ru);
       }
 
+      int cpu = sched_getcpu();
+      if (ru->ru_thread_core > -1 && cpu != ru->ru_thread_core) {
+        /* we start the ru_thread using threadCreate(), which already sets CPU
+         * affinity; let's force it here again as per feature request #732 */
+        cpu_set_t cpuset;
+        CPU_ZERO(&cpuset);
+        CPU_SET(ru->ru_thread_core, &cpuset);
+        int ret = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset);
+        AssertFatal(ret == 0, "Error in pthread_getaffinity_np(): ret: %d, errno: %d", ret, errno);
+        LOG_I(PHY, "RU %d: manually set CPU affinity to CPU %d\n", ru->idx, ru->ru_thread_core);
+      }
+
       LOG_I(PHY,"Starting IF interface for RU %d, nb_rx %d\n",ru->idx,ru->nb_rx);
       AssertFatal(ru->nr_start_if(ru,NULL) == 0, "Could not start the IF device\n");
 

radio/fhi_72/oran-init.c

@@ -78,32 +78,6 @@ static uint32_t get_nFpgaToSW_FTH_RxBufferLen(int mu)
   }
 }
 
-/* is this necessary?
-int32_t set_main_core(uint32_t main_core)
-{
-  struct sched_param sched_param;
-  cpu_set_t cpuset;
-  int32_t result = 0;
-  memset(&sched_param, 0, sizeof(struct sched_param));
-  // set main thread affinity mask to CPU2
-  sched_param.sched_priority = 99;
-  CPU_ZERO(&cpuset);
-
-  printf("This system has %d processors configured and %d processors available.\n", get_nprocs_conf(), get_nprocs());
-
-  if (main_core < get_nprocs_conf())
-    CPU_SET(main_core, &cpuset);
-  else
-    return -1;
-
-  if ((result = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset))) {
-    printf("pthread_setaffinity_np failed: coreId = 2, result = %d\n", result);
-  }
-  printf("%s [CPU %2d] [PID: %6d]\n", __FUNCTION__, sched_getcpu(), getpid());
-  return result;
-}
-*/
-
 static struct xran_prb_map get_xran_prb_map_dl(const struct xran_fh_config *f)
 {
   struct xran_prb_map prbmap = {
@@ -432,11 +406,6 @@ int *oai_oran_initialize(const openair0_config_t *openair0_cfg)
     print_fh_config(&xran_fh_config[o_xu_id]);
   }
 
-  // if ((xret = set_main_core(init.something)) < 0) {
-  //     printf("set_main_core() failed %d\n", xret);
-  //     exit(-1);
-  // }
-
   xret = xran_init(0, NULL, &init, NULL, &gxran_handle);
   if (xret != XRAN_STATUS_SUCCESS) {
     printf("xran_init failed %d\n", xret);