From 7b7eaca961b150b3430a58b6096d5f5c9aac73b3 Mon Sep 17 00:00:00 2001
From: Pedro Gonnet <pedro.gonnet@durham.ac.uk>
Date: Tue, 5 Nov 2013 17:30:27 +0000
Subject: [PATCH] added flag to wait for queue lock or not.
---
src/qsched.c | 4 ++--
src/queue.c | 13 +++++++++----
src/queue.h | 4 ++--
3 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/src/qsched.c b/src/qsched.c
index d0bfa76..e95cfda 100644
--- a/src/qsched.c
+++ b/src/qsched.c
@@ -719,7 +719,7 @@ struct task *qsched_gettask ( struct qsched *s , int qid ) {
/* Try to get a task from my own queue. */
{
TIMER_TIC
- tid = queue_get( &s->queues[qid] , s );
+ tid = queue_get( &s->queues[qid] , s , 1 );
TIMER_TOC( s , qsched_timer_queue )
if ( tid < 0 ) {
@@ -730,7 +730,7 @@ struct task *qsched_gettask ( struct qsched *s , int qid ) {
while ( naq > 0 ) {
k = rand() % naq;
TIMER_TIC2
- tid = queue_get( &s->queues[ qids[k] ] , s );
+ tid = queue_get( &s->queues[ qids[k] ] , s , 0 );
TIMER_TOC( s , qsched_timer_queue )
if ( tid < 0 )
qids[k] = qids[ --naq ];
diff --git a/src/queue.c b/src/queue.c
index 8d5022d..30d120d 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -40,11 +40,12 @@
*
* @param q The #queue.
* @param s The #sched in which this queue's tasks lives.
+ * @param insists If set, wait at the queue's lock, otherwise fail.
*
* @return The task ID or -1 if no available task could be found.
*/
-int queue_get ( struct queue *q , struct qsched *s ) {
+int queue_get ( struct queue *q , struct qsched *s , int insist ) {
int k, j, temp, tid, *inds, w, count;
struct task *tasks = s->tasks;
@@ -55,8 +56,12 @@ int queue_get ( struct queue *q , struct qsched *s ) {
/* Lock this queue. */
TIMER_TIC
- if ( lock_lock( &q->lock ) != 0 )
- error( "Failed to lock queue." );
+ if ( insist ) {
+ if ( lock_lock( &q->lock ) != 0 )
+ error( "Failed to lock queue." );
+ }
+ else if ( lock_trylock( &q->lock ) != 0 )
+ return qsched_task_none;
TIMER_TOC( s , qsched_timer_qlock );
/* Get a pointer to the indices. */
@@ -103,7 +108,7 @@ int queue_get ( struct queue *q , struct qsched *s ) {
/* Otherwise, clear the task ID. */
else
- tid = -1;
+ tid = qsched_task_none;
/* Unlock the queue. */
lock_unlock_blind( &q->lock );
diff --git a/src/queue.h b/src/queue.h
index 16895ca..10d268e 100644
--- a/src/queue.h
+++ b/src/queue.h
@@ -36,11 +36,11 @@ struct queue {
/* Maximum number of tasks in queue. */
int size;
- };
+ } __attribute__((aligned (128)));
/* Function prototypes. */
-int queue_get ( struct queue *q , struct qsched *s );
+int queue_get ( struct queue *q , struct qsched *s , int insist );
void queue_put ( struct queue *q , struct qsched *s , int tid );
void queue_init ( struct queue *q , int size );
void queue_free ( struct queue *q );
--
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