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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-06-27 13:41:12 +0200
committerIngo Molnar <mingo@elte.hu>2008-06-27 14:31:28 +0200
commitc9c294a630e28eec5f2865f028ecfc58d45c0a5a (patch)
tree62fcfc395e98ff7a4ff6bee3364d0bb86024b171
parenta7be37ac8e1565e00880531f4e2aff421a21c803 (diff)
sched: fix calc_delta_asym()
calc_delta_asym() is supposed to do the same as calc_delta_fair() except linearly shrink the result for negative nice processes - this causes them to have a smaller preemption threshold so that they are more easily preempted. The problem is that for task groups se->load.weight is the per cpu share of the actual task group weight; take that into account. Also provide a debug switch to disable the asymmetry (which I still don't like - but it does greatly benefit some workloads) This would explain the interactivity issues reported against group scheduling. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/sched_fair.c28
-rw-r--r--kernel/sched_features.h1
2 files changed, 28 insertions, 1 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 496500988ce..2268e634812 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -430,6 +430,29 @@ calc_delta_asym(unsigned long delta, struct sched_entity *se)
for_each_sched_entity(se) {
struct load_weight *se_lw = &se->load;
+#ifdef CONFIG_FAIR_SCHED_GROUP
+ struct cfs_rq *cfs_rq = se->my_q;
+ struct task_group *tg = NULL
+
+ if (cfs_rq)
+ tg = cfs_rq->tg;
+
+ if (tg && tg->shares < NICE_0_LOAD) {
+ /*
+ * scale shares to what it would have been had
+ * tg->weight been NICE_0_LOAD:
+ *
+ * weight = 1024 * shares / tg->weight
+ */
+ lw.weight *= se->load.weight;
+ lw.weight /= tg->shares;
+
+ lw.inv_weight = 0;
+
+ se_lw = &lw;
+ } else
+#endif
+
if (se->load.weight < NICE_0_LOAD)
se_lw = &lw;
@@ -1154,7 +1177,10 @@ static unsigned long wakeup_gran(struct sched_entity *se)
* More easily preempt - nice tasks, while not making it harder for
* + nice tasks.
*/
- gran = calc_delta_asym(sysctl_sched_wakeup_granularity, se);
+ if (sched_feat(ASYM_GRAN))
+ gran = calc_delta_asym(sysctl_sched_wakeup_granularity, se);
+ else
+ gran = calc_delta_fair(sysctl_sched_wakeup_granularity, se);
return gran;
}
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index afa549166d8..04123af2e67 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -7,3 +7,4 @@ SCHED_FEAT(CACHE_HOT_BUDDY, 1)
SCHED_FEAT(SYNC_WAKEUPS, 1)
SCHED_FEAT(HRTICK, 1)
SCHED_FEAT(DOUBLE_TICK, 0)
+SCHED_FEAT(ASYM_GRAN, 1)