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Commit e69b0f1b41c0e57bb1e29100b5810a5914efcb45

Authored by Peter Zijlstra
Committed by Ingo Molnar
1 parent 63859d4fe4
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

sched: Add a few SYNC hint knobs to play with 

Currently we use overlap to weaken the SYNC hint, but allow it to
set the hint as well.

 echo NO_SYNC_WAKEUP > /debug/sched_features
 echo SYNC_MORE > /debug/sched_features

preserves pipe-test behaviour without using the WF_SYNC hint.

Worth playing with on more workloads...

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 2 changed files with 21 additions and 3 deletions Side-by-side Diff

... ... @@ -1165,9 +1165,17 @@
1165 1165 load = source_load(prev_cpu, idx);
1166 1166 this_load = target_load(this_cpu, idx);
1167 1167  
1168   - if (sync && (curr->se.avg_overlap > sysctl_sched_migration_cost ||
1169   - p->se.avg_overlap > sysctl_sched_migration_cost))
1170   - sync = 0;
  1168 + if (sync) {
  1169 + if (sched_feat(SYNC_LESS) &&
  1170 + (curr->se.avg_overlap > sysctl_sched_migration_cost ||
  1171 + p->se.avg_overlap > sysctl_sched_migration_cost))
  1172 + sync = 0;
  1173 + } else {
  1174 + if (sched_feat(SYNC_MORE) &&
  1175 + (curr->se.avg_overlap < sysctl_sched_migration_cost &&
  1176 + p->se.avg_overlap < sysctl_sched_migration_cost))
  1177 + sync = 1;
  1178 + }
1171 1179  
1172 1180 /*
1173 1181 * If sync wakeup then subtract the (maximum possible)
kernel/sched_features.h
Diff comments   View file @ e69b0f1
... ... @@ -63,6 +63,16 @@
63 63 SCHED_FEAT(AFFINE_WAKEUPS, 1)
64 64  
65 65 /*
  66 + * Weaken SYNC hint based on overlap
  67 + */
  68 +SCHED_FEAT(SYNC_LESS, 1)
  69 +
  70 +/*
  71 + * Add SYNC hint based on overlap
  72 + */
  73 +SCHED_FEAT(SYNC_MORE, 0)
  74 +
  75 +/*
66 76 * Prefer to schedule the task we woke last (assuming it failed
67 77 * wakeup-preemption), since its likely going to consume data we
68 78 * touched, increases cache locality.