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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-01-14 12:39:19 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-01-15 12:00:09 +0100 |
| commit | e52fb7c097238d34f4d8e2a596f8a3f85b0c0565 (patch) | |
| tree | f846443fdf7888583b4b0ff0ddd0be1be4b37df6 /kernel/sched_features.h | |
| parent | 831451ac4e44d3a20b581ce726ef1d1144373f7d (diff) | |
| download | linux-stable-e52fb7c097238d34f4d8e2a596f8a3f85b0c0565.tar.gz linux-stable-e52fb7c097238d34f4d8e2a596f8a3f85b0c0565.tar.bz2 linux-stable-e52fb7c097238d34f4d8e2a596f8a3f85b0c0565.zip | |
sched: prefer wakers
Prefer tasks that wake other tasks to preempt quickly. This improves
performance because more work is available sooner.
The workload that prompted this patch was a kernel build over NFS4 (for some
curious and not understood reason we had to revert commit:
18de9735300756e3ca9c361ef58409d8561dfe0d to make any progress at all)
Without this patch a make -j8 bzImage (of x86-64 defconfig) would take
3m30-ish, with this patch we're down to 2m50-ish.
psql-sysbench/mysql-sysbench show a slight improvement in peak performance as
well, tbench and vmark seemed to not care.
It is possible to improve upon the build time (to 2m20-ish) but that seriously
destroys other benchmarks (just shows that there's more room for tinkering).
Much thanks to Mike who put in a lot of effort to benchmark things and proved
a worthy opponent with a competing patch.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_features.h')
| -rw-r--r-- | kernel/sched_features.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/sched_features.h b/kernel/sched_features.h index da5d93b5d2c6..76f61756e677 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -1,5 +1,6 @@ SCHED_FEAT(NEW_FAIR_SLEEPERS, 1) -SCHED_FEAT(NORMALIZED_SLEEPER, 1) +SCHED_FEAT(NORMALIZED_SLEEPER, 0) +SCHED_FEAT(ADAPTIVE_GRAN, 1) SCHED_FEAT(WAKEUP_PREEMPT, 1) SCHED_FEAT(START_DEBIT, 1) SCHED_FEAT(AFFINE_WAKEUPS, 1) |