From ed94ec26a8dae63b6c7712aea88e80577f7dbde7 Mon Sep 17 00:00:00 2001
From: Pedro Gonnet <pedro.gonnet@durham.ac.uk>
Date: Sat, 22 Jun 2013 12:18:55 +0000
Subject: [PATCH] try more than once to get a task before sleeping.
Former-commit-id: 458a6f26e877376b6bb0f74c835c04954c691959
---
src/scheduler.c | 45 +++++++++++++++++++++------------------------
src/scheduler.h | 1 +
2 files changed, 22 insertions(+), 24 deletions(-)
diff --git a/src/scheduler.c b/src/scheduler.c
index 98b2ffe790..dfa68b973f 100644
--- a/src/scheduler.c
+++ b/src/scheduler.c
@@ -662,32 +662,29 @@ struct task *scheduler_gettask ( struct scheduler *s , int qid ) {
/* Loop as long as there are tasks... */
while ( s->waiting > 0 ) {
- /* Try to get a task from the suggested queue. */
- if ( ( res = queue_gettask( &s->queues[qid] , qid , 0 ) ) != NULL )
- return res;
-
- /* If unsucessful, try stealing from the largest queue. */
- if ( s->flags & scheduler_flag_steal ) {
- int qids[ nr_queues ];
- for ( k = 0 ; k < nr_queues ; k++ )
- qids[k] = k;
- /* int max_count = 0, max_ind = 0;
- for ( k = 0 ; k < nr_queues ; k++ )
- if ( k != qid && s->queues[k].count > max_count ) {
- max_ind = k;
- max_count = s->queues[k].count;
+ /* Try more than once before sleeping. */
+ for ( int tries = 0 ; tries < scheduler_flag_maxsteal ; tries++ ) {
+
+ /* Try to get a task from the suggested queue. */
+ if ( ( res = queue_gettask( &s->queues[qid] , qid , 0 ) ) != NULL )
+ return res;
+
+ /* If unsucessful, try stealing from the largest queue. */
+ if ( s->flags & scheduler_flag_steal ){
+ int qids[ nr_queues ];
+ for ( k = 0 ; k < nr_queues ; k++ )
+ qids[k] = k;
+ for ( k = 0 ; k < nr_queues ; k++ ) {
+ int j = k + ( rand() % (nr_queues - k) );
+ int temp = qids[j];
+ qids[j] = qids[k];
+ if ( temp == qid )
+ continue;
+ if ( s->queues[temp].count > 0 && ( res = queue_gettask( &s->queues[temp] , qid , 0 ) ) != NULL )
+ return res;
}
- if ( max_count > 0 && ( res = queue_gettask( &s->queues[ max_ind ] , qid , 0 ) ) != NULL )
- return res; */
- for ( k = 0 ; k < nr_queues ; k++ ) {
- if ( k == qid )
- continue;
- int j = k + ( rand() % (nr_queues - k) );
- int temp = qids[j];
- qids[j] = qids[k];
- if ( s->queues[temp].count > 0 && ( res = queue_gettask( &s->queues[temp] , qid , 0 ) ) != NULL )
- return res;
}
+
}
/* If we failed, take a short nap. */
diff --git a/src/scheduler.h b/src/scheduler.h
index f38929d72e..b4c7b871e0 100644
--- a/src/scheduler.h
+++ b/src/scheduler.h
@@ -27,6 +27,7 @@
/* Flags . */
#define scheduler_flag_none 0
#define scheduler_flag_steal 1
+#define scheduler_flag_maxsteal 2
/* Data of a scheduler. */
--
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