ST: Refine performance when epoll_wait(0)

trunk/3rdparty/st-srs/event.c

@@ -1194,6 +1194,11 @@ ST_HIDDEN int _st_epoll_pollset_add(struct pollfd *pds, int npds)
     return 0;
 }
 
+#ifdef DEBUG
+unsigned long long _g_st_nn_epoll_wait = 0;
+unsigned long long _g_st_nn_epoll_wait_zero = 0;
+#endif
+
 ST_HIDDEN void _st_epoll_dispatch(void)
 {
     st_utime_t min_timeout;
@@ -1210,6 +1215,11 @@ ST_HIDDEN void _st_epoll_dispatch(void)
     } else {
         min_timeout = (_ST_SLEEPQ->due <= _ST_LAST_CLOCK) ? 0 : (_ST_SLEEPQ->due - _ST_LAST_CLOCK);
         timeout = (int) (min_timeout / 1000);
+
+        // At least wait 1ms when <1ms, to avoid epoll_wait spin loop.
+        if (min_timeout > 0 && timeout == 0) {
+            timeout = 1;
+        }
     }
 
     if (_st_epoll_data->pid != getpid()) {
@@ -1235,6 +1245,13 @@ ST_HIDDEN void _st_epoll_dispatch(void)
     /* Check for I/O operations */
     nfd = epoll_wait(_st_epoll_data->epfd, _st_epoll_data->evtlist, _st_epoll_data->evtlist_size, timeout);
 
+#ifdef DEBUG
+    ++_g_st_nn_epoll_wait;
+    if (timeout <= 0 && min_timeout > 0) {
+        ++_g_st_nn_epoll_wait_zero;
+    }
+#endif
+
     if (nfd > 0) {
         for (i = 0; i < nfd; i++) {
             osfd = _st_epoll_data->evtlist[i].data.fd;

trunk/src/app/srs_app_rtc_server.cpp

@@ -593,6 +593,13 @@ SrsRtcConnection* SrsRtcServer::find_session_by_username(const std::string& user
     return dynamic_cast<SrsRtcConnection*>(conn);
 }
 
+extern unsigned long long _g_st_nn_epoll_wait;
+extern unsigned long long _g_st_nn_epoll_wait_zero;
+unsigned long long _g_st_nn_epoll_wait_prev = 0;
+unsigned long long _g_st_nn_epoll_wait_zero_prev = 0;
+srs_utime_t _g_st_stat = 0;
+srs_utime_t _g_st_stat_zero = 0;
+
 srs_error_t SrsRtcServer::notify(int type, srs_utime_t interval, srs_utime_t tick)
 {
     srs_error_t err = srs_success;
@@ -630,12 +637,34 @@ srs_error_t SrsRtcServer::notify(int type, srs_utime_t interval, srs_utime_t tic
         return err;
     }
 
+    int diff_ps = 0;
+    srs_utime_t duration = srs_get_system_time() - _g_st_stat;
+    if (duration > 0) {
+        diff_ps = (_g_st_nn_epoll_wait - _g_st_nn_epoll_wait_prev) * SRS_UTIME_SECONDS / duration;
+        _g_st_nn_epoll_wait_prev = _g_st_nn_epoll_wait;
+        _g_st_stat = srs_get_system_time();
+    }
+
+    int diff_zero_bs = 0;
+    srs_utime_t duration_zero = srs_get_system_time() - _g_st_stat_zero;
+    if (duration_zero > 0) {
+        diff_zero_bs = (_g_st_nn_epoll_wait_zero - _g_st_nn_epoll_wait_zero_prev) * SRS_UTIME_SECONDS / duration_zero;
+        _g_st_nn_epoll_wait_zero_prev = _g_st_nn_epoll_wait_zero;
+        _g_st_stat_zero = srs_get_system_time();
+    }
+
+    float epoll_rate = 0;
+    if (diff_ps > 0) {
+        epoll_rate = 100.0 * diff_zero_bs / diff_ps;
+    }
+
     // Show statistics for RTC server.
     SrsProcSelfStat* u = srs_get_self_proc_stat();
     // Resident Set Size: number of pages the process has in real memory.
     int memory = (int)(u->rss * 4 / 1024);
     // TODO: FIXME: Show more data for RTC server.
-    srs_trace("RTC: Server conns=%u, cpu=%.2f%%, rss=%dMB", nn_rtc_conns, u->percent * 100, memory);
+    srs_trace("RTC: Server conns=%u, cpu=%.2f%%, rss=%dMB, epoll=%dps,%dps,%.2f%%",
+        nn_rtc_conns, u->percent * 100, memory, diff_ps, diff_zero_bs, epoll_rate);
 
     return err;
 }