* Changed the thread pool management algorithm. Detecting idle time between

  socket accepts was not working reliably on all systems, so we now follow
  the same algorithm as the Citadel server (spawn more threads when number
  of sessions < number of threads, but keep constrained to pre-defined
  minimum and maximum thread count)

diff --git a/webcit/ChangeLog b/webcit/ChangeLog
index 7a0ff9cc659befa6679f689ff69061e4c32ad7d6..79365084b917260a74323c0e95376d4efc097567 100644 (file)
--- a/webcit/ChangeLog
+++ b/webcit/ChangeLog
@@ -1,4 +1,11 @@
 $Log$
+Revision 504.2  2004/02/09 03:37:57  ajc
+* Changed the thread pool management algorithm.  Detecting idle time between
+  socket accepts was not working reliably on all systems, so we now follow
+  the same algorithm as the Citadel server (spawn more threads when number
+  of sessions < number of threads, but keep constrained to pre-defined
+  minimum and maximum thread count)
+
 Revision 504.1  2004/02/03 03:09:51  ajc
 * THIS IS 5.04
 
@@ -1636,4 +1643,3 @@ Sun Dec  6 19:50:55 EST 1998 Art Cancro <ajc@uncnsrd.mt-kisco.ny.us>
 
 1998-12-03 Nathan Bryant <bryant@cs.usm.maine.edu>
        * webserver.c: warning fix
-

diff --git a/webcit/context_loop.c b/webcit/context_loop.c
index ec6605924284dfd6ffa0b3bf725ec5069eee9f68..1832afb795466b0adc86a7f1ca9017e3c728fee0 100644 (file)
--- a/webcit/context_loop.c
+++ b/webcit/context_loop.c
@@ -61,11 +61,15 @@ void free_attachments(struct wcsession *sess) {
 void do_housekeeping(void)
 {
        struct wcsession *sptr, *ss, *session_to_kill;
+       int num_sessions = 0;
+       static int num_threads = MIN_WORKER_THREADS;
 
        do {
                session_to_kill = NULL;
                pthread_mutex_lock(&SessionListMutex);
+               num_sessions = 0;
                for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
+                       ++num_sessions;
 
                        /* Kill idle sessions */
                        if ((time(NULL) - (sptr->lastreq)) >
@@ -107,6 +111,17 @@ BREAKOUT:  pthread_mutex_unlock(&SessionListMutex);
                }
 
        } while (session_to_kill != NULL);
+
+       /*
+        * See if we need more worker threads
+        */
+       while ( (num_sessions > num_threads)
+             && (num_threads <= MAX_WORKER_THREADS) ) {
+               spawn_another_worker_thread();
+               ++num_threads;
+               lprintf(3, "There are %d sessions and %d threads active.\n",
+                       num_sessions, num_threads);
+       }
 }
 
 

diff --git a/webcit/webcit.h b/webcit/webcit.h
index 233770a1f9f3ba69728eb0ddfc0bc0d1a18ce585..eb08e8b5f77eae6ca16faf50d0bf3de2fd45fc99 100644 (file)
--- a/webcit/webcit.h
+++ b/webcit/webcit.h
@@ -37,7 +37,8 @@
 #define QU                     (3)
 #define TARGET                 "webcit01"      /* Target for inline URL's */
 #define HOUSEKEEPING           15              /* Housekeeping frequency */
-#define INITIAL_WORKER_THREADS 5
+#define MIN_WORKER_THREADS     5
+#define MAX_WORKER_THREADS     250
 #define LISTEN_QUEUE_LENGTH    100             /* listen() backlog queue */
 
 #define USERCONFIGROOM         "My Citadel Config"
@@ -427,3 +428,4 @@ void do_iconbar(void);
 void display_customize_iconbar(void);
 void commit_iconbar(void);
 int CtdlDecodeQuotedPrintable(char *decoded, char *encoded, int sourcelen);
+void spawn_another_worker_thread(void);

diff --git a/webcit/webserver.c b/webcit/webserver.c
index 7924feaeb0809ba36986277cfaee8086a2837ba5..199379dc567273d733da9d50d5502408ac31f659 100644 (file)
--- a/webcit/webserver.c
+++ b/webcit/webserver.c
@@ -307,7 +307,7 @@ int main(int argc, char **argv)
 
 
        /* Start a few initial worker threads */
-       for (i=0; i<(INITIAL_WORKER_THREADS); ++i) {
+       for (i=0; i<(MIN_WORKER_THREADS); ++i) {
                spawn_another_worker_thread();
        }
 
@@ -324,19 +324,10 @@ void worker_entry(void) {
        int ssock;
        int i = 0;
        int time_to_die = 0;
-       time_t start_time, stop_time;
 
        do {
                /* Only one thread can accept at a time */
-               start_time = time(NULL);
                ssock = accept(msock, NULL, 0);
-               stop_time = time(NULL);
-
-               /* Augment the thread pool if we're not blocking at all */
-               if ( (stop_time - start_time) == 0L) {
-                       spawn_another_worker_thread();
-               }
-
                if (ssock < 0) {
                        lprintf(2, "accept() failed: %s\n", strerror(errno));
                } else {