MT#56374 add `poller-size` config var

Change-Id: Ibd6a42f5cc5b261ce95fe0231ec78e55bd66ac31

docs/rtpengine.md

@@ -370,6 +370,13 @@ call to inject-DTMF won't be sent to __\-\-dtmf-log-dest=__ or __\-\-listen-tcp-
     So for example, if this option is set to 4, in total 8 threads will be
     launched.
 
+- __\-\-poller-size=__*INT*
+
+    Set the maximum number of event items (file descriptors) to retrieve from
+    the underlying system poll mechanism per iteration. Defaults to 128. A
+    lower number can lead to improved load-balancing among a large number of
+    threads.
+
 - __\-\-thread-stack=__*INT*
 
     Set the stack size of each thread to the value given in kB. Defaults to 2048

lib/auxlib.c

@@ -13,6 +13,7 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <sys/resource.h>
+#include <sys/epoll.h>
 #include "log.h"
 #include "loglib.h"
 
@@ -212,6 +213,7 @@ void config_load(int *argc, char ***argv, GOptionEntry *app_entries, const char
 		{ "pidfile",		'p', 0, G_OPTION_ARG_FILENAME,	&rtpe_common_config_ptr->pidfile,	"Write PID to file",			"FILE"		},
 		{ "foreground",		'f', 0, G_OPTION_ARG_NONE,	&rtpe_common_config_ptr->foreground,	"Don't fork to background",		NULL		},
 		{ "thread-stack",	0,0,	G_OPTION_ARG_INT,	&rtpe_common_config_ptr->thread_stack,	"Thread stack size in kB",		"INT"		},
+		{ "poller-size",	0,0,	G_OPTION_ARG_INT,	&rtpe_common_config_ptr->poller_size,	"Max poller items per iteration",	"INT"		},
 		{ "evs-lib-path",	0,0,	G_OPTION_ARG_FILENAME,	&rtpe_common_config_ptr->evs_lib_path,	"Location of .so for 3GPP EVS codec",	"FILE"		},
 		{ NULL, }
 	};
@@ -387,6 +389,8 @@ out:
 	if (rtpe_common_config_ptr->thread_stack == 0)
 		rtpe_common_config_ptr->thread_stack = 2048;
 
+	if (rtpe_common_config_ptr->poller_size <= 0)
+		rtpe_common_config_ptr->poller_size = 128;
 
 	return;
 

lib/auxlib.h

@@ -31,6 +31,7 @@ struct rtpengine_common_config {
 	char *pidfile;
 	int foreground;
 	int thread_stack;
+	int poller_size;
 	int max_log_line_length;
 	char *evs_lib_path;
 };

lib/poller.c

@@ -222,17 +222,17 @@ int poller_del_item(struct poller *p, int fd) {
 }
 
 
-static int poller_poll(struct poller *p, int timeout) {
+static int poller_poll(struct poller *p, int timeout, struct epoll_event *evs, int poller_size) {
 	int ret, i;
 	struct poller_item_int *it;
-	struct epoll_event evs[128], *ev, e;
+	struct epoll_event *ev, e;
 
 	if (!p)
 		return -1;
 
 	errno = 0;
 	thread_cancel_enable();
-	ret = epoll_wait(p->fd, evs, sizeof(evs) / sizeof(*evs), timeout);
+	ret = epoll_wait(p->fd, evs, poller_size, timeout);
 	thread_cancel_disable();
 
 	mutex_lock(&p->lock);
@@ -378,10 +378,18 @@ void poller_loop(void *d) {
 
 void poller_loop2(void *d) {
 	struct poller *p = d;
+	int poller_size = rtpe_common_config_ptr->poller_size;
+	struct epoll_event *evs;
+
+	evs = g_malloc(sizeof(*evs) * poller_size);
+
+	thread_cleanup_push(g_free, evs);
 
 	while (!rtpe_shutdown) {
-		int ret = poller_poll(p, thread_sleep_time);
+		int ret = poller_poll(p, thread_sleep_time, evs, poller_size);
 		if (ret < 0)
 			usleep(20 * 1000);
 	}
+
+	thread_cleanup_pop(true);
 }