FlexRAN: reimplement timers without ITTI

The timer code used to trigger periodic statistics message sending used
ITTI. Together with a high frequency reporting (e.g. 1ms), this resulted
in high CPU usage. This commit reimplements this:
* using a thread that is synchronized to the RU (if there is no MAC, we
  assume there is no RU generating a tick so we create the tick source
  ourselves)
* no RB trees but plain arrays
* smaller interface for users
* slight user interface changes
* remove stopped timer state: such timer might be simply removed
* remove one-shot timers

openair2/ENB_APP/CONTROL_MODULES/MAC/flexran_agent_mac.c

@@ -1562,11 +1562,10 @@ int flexran_agent_register_mac_xface(mid_t mod_id)
     return -1;
   }
 
-  //xface->agent_ctxt = &shared_ctxt[mod_id];
   xface->flexran_agent_send_sr_info = flexran_agent_send_sr_info;
   xface->flexran_agent_send_sf_trigger = flexran_agent_send_sf_trigger;
-  //xface->flexran_agent_send_update_mac_stats = flexran_agent_send_update_mac_stats;
   xface->flexran_agent_get_pending_dl_mac_config = flexran_agent_get_pending_dl_mac_config;
+  xface->flexran_agent_notify_tick = flexran_agent_timer_signal;
 
   xface->dl_scheduler_loaded_lib = NULL;
   xface->ul_scheduler_loaded_lib = NULL;
@@ -1689,11 +1688,10 @@ int flexran_agent_unregister_mac_xface(mid_t mod_id)
     return -1;
   }
   AGENT_MAC_xface *xface = agent_mac_xface[mod_id];
-  //xface->agent_ctxt = NULL;
   xface->flexran_agent_send_sr_info = NULL;
   xface->flexran_agent_send_sf_trigger = NULL;
-  //xface->flexran_agent_send_update_mac_stats = NULL;
   xface->flexran_agent_get_pending_dl_mac_config = NULL;
+  xface->flexran_agent_notify_tick = NULL;
 
   xface->dl_scheduler_loaded_lib = NULL;
   xface->ul_scheduler_loaded_lib = NULL;

openair2/ENB_APP/CONTROL_MODULES/MAC/flexran_agent_mac_defs.h

@@ -54,10 +54,9 @@ typedef struct {
   void (*flexran_agent_get_pending_dl_mac_config)(mid_t mod_id,
 						  Protocol__FlexranMessage **msg);
   
-  /// Notify the controller for a state change of a particular UE, by sending the proper
-  /// UE state change message (ACTIVATION, DEACTIVATION, HANDOVER)
-  // int (*flexran_agent_notify_ue_state_change)(mid_t mod_id, uint32_t rnti,
-		// 			       uint8_t state_change);
+  /// Notify the controller of another (RU) tick, i.e. new subframe. Used to
+  /// synchronize the eNB and the agent.
+  void (*flexran_agent_notify_tick)(mid_t mod_id);
   
   
   void *dl_scheduler_loaded_lib;

openair2/ENB_APP/flexran_agent.c

@@ -33,27 +33,14 @@
 #include <pthread.h>
 #include <arpa/inet.h>
 
-void *receive_thread(void *args);
-Protocol__FlexranMessage *flexran_agent_timeout(void* args);
-
-
 int agent_task_created = 0;
 /* 
  * enb agent task mainly wakes up the tx thread for periodic and oneshot messages to the controller 
  * and can interact with other itti tasks
 */
 void *flexran_agent_task(void *args){
-
-  //flexran_agent_info_t         *d = (flexran_agent_info_t *) args;
-  Protocol__FlexranMessage *msg;
-  void *data;
-  int size;
-  err_code_t err_code=0;
-  int                   priority = 0;
-
   MessageDef *msg_p = NULL;
   int         result;
-  struct flexran_agent_timer_element_s * elem = NULL;
 
   itti_mark_task_ready(TASK_FLEXRAN_AGENT);
 
@@ -72,20 +59,6 @@ void *flexran_agent_task(void *args){
       LOG_I(FLEXRAN_AGENT, "Received %s\n", ITTI_MSG_NAME(msg_p));
       break;
 
-    case TIMER_HAS_EXPIRED:
-      msg = flexran_agent_process_timeout(msg_p->ittiMsg.timer_has_expired.timer_id, msg_p->ittiMsg.timer_has_expired.arg);
-      if (msg != NULL){
-	data=flexran_agent_pack_message(msg,&size);
-	elem = get_timer_entry(msg_p->ittiMsg.timer_has_expired.timer_id);
-	if (flexran_agent_msg_send(elem->agent_id, FLEXRAN_AGENT_DEFAULT, data, size, priority)) {
-	  err_code = PROTOCOL__FLEXRAN_ERR__MSG_ENQUEUING;
-	  goto error;
-	}
-
-	LOG_D(FLEXRAN_AGENT,"sent message with size %d\n", size);
-      }
-      break;
-
     default:
       LOG_E(FLEXRAN_AGENT, "Received unexpected message %s\n", ITTI_MSG_NAME (msg_p));
       break;
@@ -93,10 +66,6 @@ void *flexran_agent_task(void *args){
 
     result = itti_free (ITTI_MSG_ORIGIN_ID(msg_p), msg_p);
     AssertFatal (result == EXIT_SUCCESS, "Failed to free memory (%d)!\n", result);
-    continue;
-  error:
-    if (err_code != 0)
-      LOG_E(FLEXRAN_AGENT,"flexran_agent_task: error %d occured\n",err_code);
   } while (1);
 
   return NULL;
@@ -245,7 +214,7 @@ int flexran_agent_start(mid_t mod_id)
    * initilize a timer 
    */ 
   
-  flexran_agent_init_timer();
+  flexran_agent_timer_init(mod_id);
 
   /* 
    * start the enb agent task for tx and interaction with the underlying network function
@@ -286,16 +255,3 @@ error:
   return 1;
 
 }
-
-Protocol__FlexranMessage *flexran_agent_timeout(void* args){
-
-  //  flexran_agent_timer_args_t *timer_args = calloc(1, sizeof(*timer_args));
-  //memcpy (timer_args, args, sizeof(*timer_args));
-  flexran_agent_timer_args_t *timer_args = (flexran_agent_timer_args_t *) args;
-  
-  LOG_UI(FLEXRAN_AGENT, "flexran_agent %d timeout\n", timer_args->mod_id);
-  //LOG_I(FLEXRAN_AGENT, "eNB action %d ENB flags %d \n", timer_args->cc_actions,timer_args->cc_report_flags);
-  //LOG_I(FLEXRAN_AGENT, "UE action %d UE flags %d \n", timer_args->ue_actions,timer_args->ue_report_flags);
-  
-  return NULL;
-}

openair2/ENB_APP/flexran_agent_common.h

@@ -150,10 +150,15 @@ Protocol__FlexranMessage* flexran_agent_handle_message (mid_t mod_id,
 						    uint32_t size);
 
 /* Function to be used to send a message to a dispatcher once the appropriate event is triggered. */
-Protocol__FlexranMessage *flexran_agent_handle_timed_task(void *args);
+Protocol__FlexranMessage *flexran_agent_handle_timed_task(
+                mid_t mod_id,
+                Protocol__FlexranMessage *msg);
 
 /*Top level Statistics hanlder*/
-Protocol__FlexranMessage *flexran_agent_send_stats_reply(void *args);
+Protocol__FlexranMessage *flexran_agent_send_stats_reply(
+                mid_t mod_id,
+                const Protocol__FlexranMessage *msg);
+
 int flexran_agent_handle_stats(mid_t mod_id, const void *params, Protocol__FlexranMessage **msg);
 
 /* Function to be used to handle reply message . */

openair2/ENB_APP/flexran_agent_defs.h

@@ -107,36 +107,6 @@ typedef uint8_t lcid_t;
 typedef int32_t  err_code_t; 
 
 
-/*---------Timer Enums --------- */
-
-typedef enum {
-  /* oneshot timer:  */
-  FLEXRAN_AGENT_TIMER_TYPE_ONESHOT = 0,
-
-  /* periodic timer  */
-  FLEXRAN_AGENT_TIMER_TYPE_PERIODIC = 1,
-
-  /* Inactive state: initial state for any timer. */
-  FLEXRAN_AGENT_TIMER_TYPE_EVENT_DRIVEN = 2,
-  
-  /* Max number of states available */
-  FLEXRAN_AGENT_TIMER_TYPE_MAX,
-} flexran_agent_timer_type_t;
-
-
-typedef enum {
-  /* Inactive state: initial state for any timer. */
-  FLEXRAN_AGENT_TIMER_STATE_INACTIVE = 0x0,
-
-  /* Inactive state: initial state for any timer. */
-  FLEXRAN_AGENT_TIMER_STATE_ACTIVE = 0x1,
-
-  /* Inactive state: initial state for any timer. */
-  FLEXRAN_AGENT_TIMER_STATE_STOPPED = 0x2,
-  
-  /* Max number of states available */
-  FLEXRAN_AGENT_TIMER_STATE_MAX,
-} flexran_agent_timer_state_t;
 
 #define FLEXRAN_CAP_LOPHY(cApS) (((cApS) & (1 << PROTOCOL__FLEX_BS_CAPABILITY__LOPHY)) > 0)
 #define FLEXRAN_CAP_HIPHY(cApS) (((cApS) & (1 << PROTOCOL__FLEX_BS_CAPABILITY__HIPHY)) > 0)

openair2/ENB_APP/flexran_agent_handler.c

@@ -154,39 +154,20 @@ void * flexran_agent_pack_message(Protocol__FlexranMessage *msg,
   return NULL;   
 }
 
-Protocol__FlexranMessage *flexran_agent_handle_timed_task(void *args) {
+Protocol__FlexranMessage *flexran_agent_handle_timed_task(
+      mid_t mod_id,
+      Protocol__FlexranMessage *msg) {
   err_code_t err_code;
-  flexran_agent_timer_args_t *timer_args = (flexran_agent_timer_args_t *) args;
 
-  Protocol__FlexranMessage *timed_task, *reply_message;
-  timed_task = timer_args->msg;
-  err_code = ((*agent_messages_callback[timed_task->msg_case-1][timed_task->msg_dir-1])(timer_args->mod_id, (void *) timed_task, &reply_message));
-  if ( err_code < 0 ){
-    goto error;
+  Protocol__FlexranMessage *reply_message;
+  err_code = ((*agent_messages_callback[msg->msg_case-1][msg->msg_dir-1])(
+                      mod_id, msg, &reply_message));
+  if (err_code < 0) {
+    LOG_E(FLEXRAN_AGENT, "could not handle message: errno %d occured\n", err_code);
+    return NULL;
   }
 
   return reply_message;
-  
- error:
-  LOG_E(FLEXRAN_AGENT,"errno %d occured\n",err_code);
-  return NULL;
-}
-
-Protocol__FlexranMessage* flexran_agent_process_timeout(long timer_id, void* timer_args){
-    
-  struct flexran_agent_timer_element_s *found = get_timer_entry(timer_id);
- 
-  if (found == NULL ) goto error;
-  LOG_D(FLEXRAN_AGENT, "Found the entry (%p): timer_id is 0x%lx  0x%lx\n", found, timer_id, found->timer_id);
-  
-  if (timer_args == NULL)
-    LOG_W(FLEXRAN_AGENT,"null timer args\n");
-  
-  return found->cb(timer_args);
-
- error:
-  LOG_E(FLEXRAN_AGENT, "can't get the timer element\n");
-  return NULL;
 }
 
 err_code_t flexran_agent_destroy_flexran_message(Protocol__FlexranMessage *msg) {
@@ -209,24 +190,21 @@ int flexran_agent_handle_stats(mid_t mod_id, const void *params, Protocol__Flexr
     return -1;
   }
   Protocol__FlexCompleteStatsRequest *comp_req = stats_req->complete_stats_request;
-  flexran_agent_timer_args_t *timer_args = NULL;
 
   switch (comp_req->report_frequency) {
   case PROTOCOL__FLEX_STATS_REPORT_FREQ__FLSRF_OFF:
-    flexran_agent_destroy_timer_by_task_id(xid);
+    flexran_agent_destroy_timer(mod_id, xid);
     return 0;
   case PROTOCOL__FLEX_STATS_REPORT_FREQ__FLSRF_ONCE:
     LOG_E(FLEXRAN_AGENT, "one-shot timer not implemented yet\n");
     return -1;
   case PROTOCOL__FLEX_STATS_REPORT_FREQ__FLSRF_PERIODICAL:
     /* Create a one off flexran message as an argument for the periodical task */
-    timer_args = calloc(1, sizeof(flexran_agent_timer_args_t));
-    AssertFatal(timer_args, "cannot allocate memory for timer\n");
-    timer_args->mod_id = mod_id;
-    timer_args->msg = input;
+    LOG_I(FLEXRAN_AGENT, "periodical timer xid %d cell_flags %d ue_flags %d\n",
+          xid, comp_req->cell_report_flags, comp_req->ue_report_flags);
     flexran_agent_create_timer(mod_id, comp_req->sf,
                                FLEXRAN_AGENT_TIMER_TYPE_PERIODIC, xid,
-                               flexran_agent_send_stats_reply, timer_args);
+                               flexran_agent_send_stats_reply, input);
     /* return 1: do not dispose comp_req message we received, we still need it */
     return 1;
   case PROTOCOL__FLEX_STATS_REPORT_FREQ__FLSRF_CONTINUOUS:
@@ -241,15 +219,14 @@ int flexran_agent_handle_stats(mid_t mod_id, const void *params, Protocol__Flexr
 /*
   Top level reply 
  */
-Protocol__FlexranMessage *flexran_agent_send_stats_reply(void *args) {
-  const flexran_agent_timer_args_t *timer_args = args;
-  const mid_t enb_id = timer_args->mod_id;
-  const Protocol__FlexranMessage *input = (Protocol__FlexranMessage *)timer_args->msg;
-  const Protocol__FlexStatsRequest *stats_req = input->stats_request_msg;
+Protocol__FlexranMessage *flexran_agent_send_stats_reply(
+      mid_t                           mod_id,
+      const Protocol__FlexranMessage *msg) {
+  const Protocol__FlexStatsRequest *stats_req = msg->stats_request_msg;
   const xid_t xid = stats_req->header->xid;
 
   Protocol__FlexranMessage *reply = NULL;
-  err_code_t rc = flexran_agent_stats_reply(enb_id, xid, stats_req, &reply);
+  err_code_t rc = flexran_agent_stats_reply(mod_id, xid, stats_req, &reply);
   if (rc < 0) {
     LOG_E(FLEXRAN_AGENT, "%s(): errno %d occured, cannot send stats_reply\n",
           __func__, rc);

openair2/ENB_APP/flexran_agent_timer.h

@@ -26,100 +26,45 @@
  * \version 0.1
  */
 
-#include <stdio.h>
-#include <time.h>
+#ifndef _FLEXRAN_AGENT_TIMER_
+#define _FLEXRAN_AGENT_TIMER_
 
 #include "flexran_agent_common.h"
-#include "flexran_agent_common_internal.h"
-#include "flexran_agent_extern.h"
 #include "flexran_agent_defs.h"
 
-
-# include "tree.h"
-# include "intertask_interface.h"
-
-
-
-/*******************
- * timer primitves
- *******************/
-
 #define TIMER_NULL                 -1 
 #define TIMER_TYPE_INVALIDE        -2
 #define	TIMER_SETUP_FAILED         -3
 #define	TIMER_REMOVED_FAILED       -4
 #define	TIMER_ELEMENT_NOT_FOUND    -5
 
+typedef enum {
+  FLEXRAN_AGENT_TIMER_TYPE_ONESHOT,
+  FLEXRAN_AGENT_TIMER_TYPE_PERIODIC,
+} flexran_agent_timer_type_t;
 
 /* Type of the callback executed when the timer expired */
-typedef Protocol__FlexranMessage *(*flexran_agent_timer_callback_t)(void*);
-
-
-typedef struct flexran_agent_timer_args_s{
-  mid_t            mod_id;
-  Protocol__FlexranMessage *msg;
-} flexran_agent_timer_args_t;
-
-
-typedef struct flexran_agent_timer_element_s{
-  RB_ENTRY(flexran_agent_timer_element_s) entry;
-
-  agent_id_t             agent_id;
-  instance_t       instance;
-  
-  flexran_agent_timer_type_t  type;
-  flexran_agent_timer_state_t state;
+typedef Protocol__FlexranMessage *(*flexran_agent_timer_callback_t)(
+    mid_t mod_id, const Protocol__FlexranMessage *msg);
 
-  uint32_t interval_sec;
-  uint32_t interval_usec;
+err_code_t flexran_agent_timer_init(mid_t mod_id);
+void       flexran_agent_timer_exit(mid_t mod_id);
 
-  long timer_id;  /* Timer id returned by the timer API*/
-  xid_t xid; /*The id of the task as received by the controller
-	       message*/
-  
-  flexran_agent_timer_callback_t cb;
-  flexran_agent_timer_args_t *timer_args;
-  
-} flexran_agent_timer_element_t;
-
-typedef struct flexran_agent_timer_instance_s{
-  RB_HEAD(flexran_agent_map, flexran_agent_timer_element_s) flexran_agent_head;
-}flexran_agent_timer_instance_t;
-
-
-err_code_t flexran_agent_init_timer(void);
+/* Signals next subframe for FlexRAN timers */
+void flexran_agent_timer_signal(mid_t mod_id);
 
 /* Create a timer for some agent related event with id xid. */
 err_code_t flexran_agent_create_timer(mid_t    mod_id,
                                       uint32_t sf,
-                                      uint32_t timer_type,
+                                      flexran_agent_timer_type_t timer_type,
                                       xid_t    xid,
                                       flexran_agent_timer_callback_t cb,
-                                      void    *timer_args);
+                                      Protocol__FlexranMessage *msg);
 
 /* Destroy all existing timers */
-err_code_t flexran_agent_destroy_timers(void);
-
-/* Destroy the timer with the given timer_id */
-err_code_t flexran_agent_destroy_timer(long timer_id);
+err_code_t flexran_agent_destroy_timers(mid_t mod_id);
 
 /* Destroy the timer for task with id xid */
-err_code_t flexran_agent_destroy_timer_by_task_id(xid_t xid);
-
-/* Stop a timer */
-err_code_t flexran_agent_stop_timer(long timer_id);
-
-/* Restart the given timer */
-err_code_t flexran_agent_restart_timer(long *timer_id);
-
-/* Find the timer with the given timer_id */
-struct flexran_agent_timer_element_s * get_timer_entry(long timer_id);
-
-/* Obtain the protocol message stored in the given expired timer */
-Protocol__FlexranMessage * flexran_agent_process_timeout(long timer_id, void* timer_args);
-
-/* Comparator function comparing two timers. Decides the ordering of the timers */
-int flexran_agent_compare_timer(struct flexran_agent_timer_element_s *a, struct flexran_agent_timer_element_s *b);
+err_code_t flexran_agent_destroy_timer(mid_t mod_id, xid_t xid);
 
-/* RB_PROTOTYPE is for .h files */
-RB_PROTOTYPE(flexran_agent_map, flexran_agent_timer_element_s, entry, flexran_agent_compare_timer);
+#endif /* _FLEXRAN_AGENT_TIMER_ */

openair2/LAYER2/MAC/eNB_scheduler.c

@@ -988,6 +988,8 @@ eNB_dlsch_ulsch_scheduler(module_id_t module_idP,
   if (flexran_agent_get_mac_xface(module_idP) && subframeP == 9) {
     flexran_agent_slice_update(module_idP);
   }
+  if (flexran_agent_get_mac_xface(module_idP))
+    flexran_agent_get_mac_xface(module_idP)->flexran_agent_notify_tick(module_idP);
 
   stop_meas(&(eNB->eNB_scheduler));
   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_ENB_DLSCH_ULSCH_SCHEDULER, VCD_FUNCTION_OUT);