From 84f1a0f0ac232d9b6b9b785dd515701245a95acd Mon Sep 17 00:00:00 2001
From: Dave West <davew@uncensored.citadel.org>
Date: Mon, 2 Nov 2009 13:15:52 +0000
Subject: [PATCH] Added a new command line option to citserver "-s" takes a
 numerical parameter. When this is specified with a number greater than 0 the
 server will start almost as normal except it will not start any workers or
 module related threads. Instead it will create the specified number of
 simulation threads and time how long it takes for them to be created, create
 a context, delete the context and get cleaned up. A message is written to the
 log stating how long it took and then the server will exit normally.

This is to help tune the client connection code and thread creation stuff.
---
 citadel/server_main.c |  7 +++++-
 citadel/threads.c     | 51 ++++++++++++++++++++++++++++++++++++++++---
 citadel/threads.h     |  1 +
 3 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/citadel/server_main.c b/citadel/server_main.c
index 5d73d7a52..66093245c 100644
--- a/citadel/server_main.c
+++ b/citadel/server_main.c
@@ -121,6 +121,11 @@ int main(int argc, char **argv)
 			running_as_daemon = 1;
 		}
 
+		/* run a few stats if -s was specified */
+		else if (!strncmp(argv[a], "-s", 2)) {
+			statcount = atoi(&argv[a][2]);
+		}
+
 		/* -x specifies the desired logging level */
 		else if (!strncmp(argv[a], "-x", 2)) {
 			verbosity = atoi(&argv[a][2]);
@@ -155,7 +160,7 @@ int main(int argc, char **argv)
 			CtdlLogPrintf(CTDL_EMERG,	"citserver: usage: "
 					"citserver "
 					"[-lLogFacility] "
-					"[-d] [-D] "
+					"[-d] [-D] [-s]"
 					" [-tTraceFile]"
 					" [-xLogLevel] [-hHomeDir]\n");
 			exit(1);
diff --git a/citadel/threads.c b/citadel/threads.c
index 9782d05fc..aa6636e0a 100644
--- a/citadel/threads.c
+++ b/citadel/threads.c
@@ -60,6 +60,8 @@
 
 static int num_threads = 0;			/* Current number of threads */
 static int num_workers = 0;			/* Current number of worker threads */
+long statcount = 0;		/* are we doing a stats check? */
+static long stats_done = 0;
 
 CtdlThreadNode *CtdlThreadList = NULL;
 CtdlThreadNode *CtdlThreadSchedList = NULL;
@@ -1232,11 +1234,38 @@ void *new_worker_thread(void *arg);
 extern void close_masters (void);
 
 
+void *simulation_worker (void*arg) {
+	struct CitContext *this;
+
+	this = CreateNewContext();
+	this->kill_me = 1;
+	this->state = CON_IDLE;
+	dead_session_purge(1);
+	begin_critical_section(S_SESSION_TABLE);
+	stats_done++;
+	end_critical_section(S_SESSION_TABLE);
+	return NULL;
+}
+
+
+void *simulation_thread (void *arg)
+{
+	long stats = statcount;
+
+	while(stats) {
+		CtdlThreadCreate("Connection simulation worker", CTDLTHREAD_BIGSTACK, simulation_worker, NULL);
+		stats--;
+	}
+	CtdlThreadStopAll();
+	return NULL;
+}
 
 void go_threading(void)
 {
 	int i;
 	CtdlThreadNode *last_worker;
+	struct timeval start, now, result;
+	double last_duration;
 	
 	/*
 	 * Initialise the thread system
@@ -1244,7 +1273,14 @@ void go_threading(void)
 	ctdl_thread_internal_init();
 
 	/* Second call to module init functions now that threading is up */
-	initialise_modules(1);
+	if (!statcount)
+		initialise_modules(1);
+	else {
+		CtdlLogPrintf(CTDL_EMERG, "Running connection simulation stats\n");
+		gettimeofday(&start, NULL);
+		CtdlThreadCreate("Connection simulation master", CTDLTHREAD_BIGSTACK, simulation_thread, NULL);
+	}
+
 
 	/*
 	 * This thread is now used for garbage collection of other threads in the thread list
@@ -1314,6 +1350,7 @@ void go_threading(void)
 		/* FIXME: come up with a better way to dynamically alter the number of threads
 		 * based on the system load
 		 */
+		if (!statcount) {
 #ifdef NEW_WORKER
 		if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkers() <= num_sessions) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
 #else
@@ -1341,7 +1378,8 @@ void go_threading(void)
 			else
 				CtdlLogPrintf (CTDL_WARNING, "Server strangled due to machine load average too high.\n");
 		}
-		
+		}
+
 		CtdlThreadGC();
 
 		if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
@@ -1352,7 +1390,7 @@ void go_threading(void)
 #ifdef THREADS_USESIGNALS
 		if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
 #else
-		if (CtdlThreadGetCount())
+		if (CtdlThreadGetCount() && !statcount)
 #endif
 			CtdlThreadSleep(1);
 	}
@@ -1360,6 +1398,13 @@ void go_threading(void)
 	 * If the above loop exits we must be shutting down since we obviously have no threads
 	 */
 	ctdl_thread_internal_cleanup();
+
+	if (statcount) {
+		gettimeofday(&now, NULL);
+		timersub(&now, &start, &result);
+		last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
+		CtdlLogPrintf(CTDL_EMERG, "Simulated %ld connections in %f seconds\n", stats_done, last_duration);
+	}
 }
 
 
diff --git a/citadel/threads.h b/citadel/threads.h
index 9efebbbbd..4f4830639 100644
--- a/citadel/threads.h
+++ b/citadel/threads.h
@@ -126,6 +126,7 @@ struct ThreadTSD {
 
 extern double CtdlThreadLoadAvg;
 extern double CtdlThreadWorkerAvg;
+extern long statcount;		/* are we doing a stats check? */
 extern citthread_key_t ThreadKey;
 
 void ctdl_thread_internal_init_tsd(void);
-- 
2.30.2