From d70cac0e6b5920d2eb08ab48df6628df932a9081 Mon Sep 17 00:00:00 2001 From: phk Date: Mon, 9 Jun 2008 08:35:38 +0000 Subject: [PATCH] Style & Polish. git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@2656 d4fa192b-c00b-0410-8231-f00ffab90ce4 --- varnish-cache/bin/varnishd/cache_pool.c | 65 ++++++++++++++++--------- 1 file changed, 41 insertions(+), 24 deletions(-) diff --git a/varnish-cache/bin/varnishd/cache_pool.c b/varnish-cache/bin/varnishd/cache_pool.c index c0cec43e..ed53ca2f 100644 --- a/varnish-cache/bin/varnishd/cache_pool.c +++ b/varnish-cache/bin/varnishd/cache_pool.c @@ -28,7 +28,18 @@ * * $Id$ * - * XXX: automatic thread-pool size adaptation. + * We maintain a number of worker thread pools, to spread lock contention. + * + * Pools can be added on the fly, as a means to mitigate lock contention, + * but can only be removed again by a restart. (XXX: we could fix that) + * + * Two threads herd the pools, one eliminates idle threads and aggregates + * statistics for all the pools, the other thread creates new threads + * on demand, subject to various numerical constraints. + * + * The algorithm for when to create threads needs to be reactive enough + * to handle startup spikes, but sufficiently attenuated to not cause + * thread pileups. This remains subject for improvement. */ #include "config.h" @@ -188,24 +199,6 @@ WRK_Sendfile(struct worker *w, int fd, off_t off, unsigned len) /*--------------------------------------------------------------------*/ -static void -wrk_do_cnt_sess(struct worker *w, void *priv) -{ - struct sess *sess; - - CAST_OBJ_NOTNULL(sess, priv, SESS_MAGIC); - sess->wrk = w; - CHECK_OBJ_ORNULL(w->nobj, OBJECT_MAGIC); - CHECK_OBJ_ORNULL(w->nobjhead, OBJHEAD_MAGIC); - w->used = NAN; - CNT_Session(sess); - assert(!isnan(w->used)); - CHECK_OBJ_ORNULL(w->nobj, OBJECT_MAGIC); - CHECK_OBJ_ORNULL(w->nobjhead, OBJHEAD_MAGIC); -} - -/*--------------------------------------------------------------------*/ - static void * wrk_thread(void *priv) { @@ -269,7 +262,11 @@ wrk_thread(void *priv) return (NULL); } -/*--------------------------------------------------------------------*/ +/*-------------------------------------------------------------------- + * Queue a workrequest if possible. + * + * Return zero if the request was queued, negative if it wasn't. + */ int WRK_Queue(struct workreq *wrq) @@ -302,8 +299,7 @@ WRK_Queue(struct workreq *wrq) return (0); } - /* If we have too much in the overflow already, refuse */ - + /* If we have too much in the overflow already, refuse. */ if (qp->nqueue > ovfl_max) { qp->ndrop++; UNLOCK(&qp->mtx); @@ -320,6 +316,24 @@ WRK_Queue(struct workreq *wrq) /*--------------------------------------------------------------------*/ +static void +wrk_do_cnt_sess(struct worker *w, void *priv) +{ + struct sess *sess; + + CAST_OBJ_NOTNULL(sess, priv, SESS_MAGIC); + sess->wrk = w; + CHECK_OBJ_ORNULL(w->nobj, OBJECT_MAGIC); + CHECK_OBJ_ORNULL(w->nobjhead, OBJHEAD_MAGIC); + w->used = NAN; + CNT_Session(sess); + assert(!isnan(w->used)); + CHECK_OBJ_ORNULL(w->nobj, OBJECT_MAGIC); + CHECK_OBJ_ORNULL(w->nobjhead, OBJHEAD_MAGIC); +} + +/*--------------------------------------------------------------------*/ + void WRK_QueueSession(struct sess *sp) { @@ -346,7 +360,9 @@ WRK_QueueSession(struct sess *sp) SES_Delete(sp); } -/*--------------------------------------------------------------------*/ +/*-------------------------------------------------------------------- + * Add (more) thread pools + */ static void wrk_addpools(const unsigned pools) @@ -466,7 +482,7 @@ wrk_herdtimer_thread(void *priv) } /*-------------------------------------------------------------------- - * Create more threads, if necessay & possible + * Create another thread, if necessary & possible */ static void @@ -540,6 +556,7 @@ WRK_Init(void) AZ(pthread_mutex_init(&herder_mtx, NULL)); AZ(pthread_create(&tp, NULL, wrk_herdtimer_thread, NULL)); + AZ(pthread_detach(tp)); AZ(pthread_create(&tp, NULL, wrk_herder_thread, NULL)); AZ(pthread_detach(tp)); } -- 2.39.5