Commit 143fc83e authored by Greg Ames's avatar Greg Ames
Browse files

Speed up the server's response to a spike in incoming workload 

or restarts.

New processes aren't able to start all their threads right away
if other dying processes share the same scoreboard real estate.
So give empty process slots in the scoreboard top priority.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89928 13f79535-47bb-0310-9956-ffa450edef68
parent cdbd736e

CHANGES

+4 −0
Original line number Diff line number Diff line 
Changes with Apache 2.0.23-dev



  *) Speed up the server's response to a spike in incoming workload

     or restarts by assigning empty scoreboard slots to new processes

     when they are available.  [Greg Ames]



  *) Add a handler to mod_includes.c.  This handler is designed to

     implement the XbitHack directive.  This can't be done with a

     fixup, because we need to check the content-type, which is

server/mpm/threaded/threaded.c

+28 −5
Original line number Diff line number Diff line
@@ -973,6 +973,7 @@ static void perform_idle_server_maintenance(void) 
    worker_score *ws;

    process_score *ps;

    int free_length;

    int totally_free_length = 0;

    int free_slots[MAX_SPAWN_RATE];

    int last_non_dead;

    int total_non_dead;
@@ -993,16 +994,21 @@ static void perform_idle_server_maintenance(void) 
	int status = SERVER_DEAD;

	int any_dying_threads = 0;

	int any_dead_threads = 0;

	int all_dead_threads = 1;



	if (i >= ap_max_daemons_limit && free_length == idle_spawn_rate)

	if (i >= ap_max_daemons_limit && totally_free_length == idle_spawn_rate)

	    break;

        ps = &ap_scoreboard_image->parent[i];

	for (j = 0; j < ap_threads_per_child; j++) {

            ws = &ap_scoreboard_image->servers[i][j];

	    status = ws->status;



            /* XXX any_dying_threads is probably no longer needed    GLA */

	    any_dying_threads = any_dying_threads || (status == SERVER_GRACEFUL);

	    any_dead_threads = any_dead_threads || (status == SERVER_DEAD);

	    all_dead_threads = all_dead_threads &&

                                   (status == SERVER_DEAD ||

                                    status == SERVER_GRACEFUL);



	    /* We consider a starting server as idle because we started it

	     * at least a cycle ago, and if it still hasn't finished starting
@@ -1020,13 +1026,28 @@ static void perform_idle_server_maintenance(void) 
	        ++idle_thread_count;

	    }

	}

        /* XXX any_dead_threads may not be needed any more GLA */

        if (any_dead_threads && free_length < idle_spawn_rate 

        if (any_dead_threads && totally_free_length < idle_spawn_rate 

                && (!ps->pid               /* no process in the slot */

                    || ps->quiescing)) {   /* or at least one is going away */

            if (all_dead_threads) {

                /* great! we prefer these, because the new process can

                 * start more threads sooner.  So prioritize this slot 

                 * by putting it ahead of any slots with active threads.

                 *

                 * first, make room by moving a slot that's potentially still

                 * in use to the end of the array

                 */

                free_slots[free_length] = free_slots[totally_free_length];

                free_slots[totally_free_length++] = i;

            }

            else {

                /* slot is still in use - back of the bus

                 */

	        free_slots[free_length] = i;

            }

	    ++free_length;

	}

        /* XXX if (!ps->quiescing)     is probably more reliable  GLA */

	if (!any_dying_threads) {

            last_non_dead = i;

            ++total_non_dead;
@@ -1057,7 +1078,9 @@ static void perform_idle_server_maintenance(void) 
	    idle_spawn_rate = 1;

	}

	else {

	    

            if (free_length > idle_spawn_rate) {

                free_length = idle_spawn_rate;

            }

	    if (idle_spawn_rate >= 8) {

	        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0, ap_server_conf,

			     "server seems busy, (you may need "

server/mpm/worker/worker.c

+27 −4
Original line number Diff line number Diff line
@@ -1023,6 +1023,7 @@ static void perform_idle_server_maintenance(void) 
    worker_score *ws;

    process_score *ps;

    int free_length;

    int totally_free_length = 0;

    int free_slots[MAX_SPAWN_RATE];

    int last_non_dead;

    int total_non_dead;
@@ -1043,16 +1044,21 @@ static void perform_idle_server_maintenance(void) 
	int status = SERVER_DEAD;

	int any_dying_threads = 0;

	int any_dead_threads = 0;

	int all_dead_threads = 1;



	if (i >= ap_max_daemons_limit && free_length == idle_spawn_rate)

	if (i >= ap_max_daemons_limit && totally_free_length == idle_spawn_rate)

	    break;

        ps = &ap_scoreboard_image->parent[i];

	for (j = 0; j < ap_threads_per_child; j++) {

            ws = &ap_scoreboard_image->servers[i][j];

	    status = ws->status;



            /* XXX any_dying_threads is probably no longer needed    GLA */

	    any_dying_threads = any_dying_threads || (status == SERVER_GRACEFUL);

	    any_dead_threads = any_dead_threads || (status == SERVER_DEAD);

	    all_dead_threads = all_dead_threads &&

                                   (status == SERVER_DEAD ||

                                    status == SERVER_GRACEFUL);



	    /* We consider a starting server as idle because we started it

	     * at least a cycle ago, and if it still hasn't finished starting
@@ -1070,13 +1076,28 @@ static void perform_idle_server_maintenance(void) 
	        ++idle_thread_count;

	    }

	}

        /* XXX any_dead_threads may not be needed any more GLA */

        if (any_dead_threads && free_length < idle_spawn_rate 

        if (any_dead_threads && totally_free_length < idle_spawn_rate 

                && (!ps->pid               /* no process in the slot */

                    || ps->quiescing)) {   /* or at least one is going away */

            if (all_dead_threads) {

                /* great! we prefer these, because the new process can

                 * start more threads sooner.  So prioritize this slot 

                 * by putting it ahead of any slots with active threads.

                 *

                 * first, make room by moving a slot that's potentially still

                 * in use to the end of the array

                 */

                free_slots[free_length] = free_slots[totally_free_length];

                free_slots[totally_free_length++] = i;

            }

            else {

                /* slot is still in use - back of the bus

                 */

	    free_slots[free_length] = i;

            }

	    ++free_length;

	}

        /* XXX if (!ps->quiescing)     is probably more reliable  GLA */

	if (!any_dying_threads) {

            last_non_dead = i;

            ++total_non_dead;
@@ -1107,7 +1128,9 @@ static void perform_idle_server_maintenance(void) 
	    idle_spawn_rate = 1;

	}

	else {

	    

            if (free_length > idle_spawn_rate) {

                free_length = idle_spawn_rate;

            }

	    if (idle_spawn_rate >= 8) {

	        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0, ap_server_conf,

			     "server seems busy, (you may need "