From 4fe80ee1333f14db784fb8ab8fe411d75910278c Mon Sep 17 00:00:00 2001
From: Pedro Gonnet <pedro.gonnet@durham.ac.uk>
Date: Sat, 6 Apr 2013 20:08:27 +0000
Subject: [PATCH] more civilized way of dealing with fixed time-steps.
Former-commit-id: 3102b06a40327392ec4313bba788536ce71697ec
---
src/engine.c | 45 ++++++++++++++++++++++++++-------------------
src/engine.h | 1 +
src/queue.c | 9 +++------
3 files changed, 30 insertions(+), 25 deletions(-)
diff --git a/src/engine.c b/src/engine.c
index 43e3c21b4b..c75ca2e5dd 100644
--- a/src/engine.c
+++ b/src/engine.c
@@ -411,10 +411,13 @@ void engine_step ( struct engine *e , int sort_queues ) {
TIMER_TIC2
/* Get the maximum dt. */
- dt_step = 2.0f*dt;
- for ( k = 0 ; k < 32 && (e->step & (1 << k)) == 0 ; k++ )
- dt_step *= 2;
- // dt_step = FLT_MAX;
+ if ( e->policy & engine_policy_fixdt )
+ dt_step = FLT_MAX;
+ else {
+ dt_step = 2.0f*dt;
+ for ( k = 0 ; k < 32 && (e->step & (1 << k)) == 0 ; k++ )
+ dt_step *= 2;
+ }
/* Set the maximum dt. */
e->dt_step = dt_step;
@@ -493,24 +496,28 @@ void engine_step ( struct engine *e , int sort_queues ) {
e->step += 1;
/* Does the time step need adjusting? */
- if ( e->dt == 0 ) {
+ if ( e->policy & engine_policy_fixdt )
e->dt = e->dt_orig;
- while ( dt_min < e->dt )
- e->dt *= 0.5;
- while ( dt_min > 2*e->dt )
- e->dt *= 2.0;
- printf( "engine_step: dt_min=%.3e, adjusting time step to dt=%e.\n" , dt_min , e->dt );
- }
else {
- while ( dt_min < e->dt ) {
- e->dt *= 0.5;
- e->step *= 2;
- printf( "engine_step: dt_min dropped below time step, adjusting to dt=%e.\n" , e->dt );
+ if ( e->dt == 0 ) {
+ e->dt = e->dt_orig;
+ while ( dt_min < e->dt )
+ e->dt *= 0.5;
+ while ( dt_min > 2*e->dt )
+ e->dt *= 2.0;
+ printf( "engine_step: dt_min=%.3e, adjusting time step to dt=%e.\n" , dt_min , e->dt );
}
- while ( dt_min > 2*e->dt && (e->step & 1) == 0 ) {
- e->dt *= 2.0;
- e->step /= 2;
- printf( "engine_step: dt_min is larger than twice the time step, adjusting to dt=%e.\n" , e->dt );
+ else {
+ while ( dt_min < e->dt ) {
+ e->dt *= 0.5;
+ e->step *= 2;
+ printf( "engine_step: dt_min dropped below time step, adjusting to dt=%e.\n" , e->dt );
+ }
+ while ( dt_min > 2*e->dt && (e->step & 1) == 0 ) {
+ e->dt *= 2.0;
+ e->step /= 2;
+ printf( "engine_step: dt_min is larger than twice the time step, adjusting to dt=%e.\n" , e->dt );
+ }
}
}
diff --git a/src/engine.h b/src/engine.h
index 12c3d9d814..5d332ad88a 100644
--- a/src/engine.h
+++ b/src/engine.h
@@ -25,6 +25,7 @@
#define engine_policy_steal 2
#define engine_policy_keep 4
#define engine_policy_block 8
+#define engine_policy_fixdt 16
#define engine_queue_scale 1.2
diff --git a/src/queue.c b/src/queue.c
index e1a41a9b73..664011f170 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -89,17 +89,14 @@ int queue_counter[ queue_counter_count ];
void queue_insert ( struct queue *q , struct task *t ) {
- int k;
-
/* Lock the queue. */
if ( lock_lock( &q->lock ) != 0 )
error( "Failed to get queue lock." );
- /* Bubble-up the tasks. */
- for ( k = q->count ; k > q->next ; k-- )
- q->tid[k] = q->tid[k-1];
- q->tid[ q->next ] = t - q->tasks;
+ /* Swap next task to end. */
+ q->tid[ q->count ] = q->tid[ q->next ];
q->count += 1;
+ q->tid[ q->next ] = t - q->tasks;
q->next += 1;
/* Unlock the queue. */
--
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