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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-01-14 12:39:19 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-01-15 12:00:09 +0100 |
commit | e52fb7c097238d34f4d8e2a596f8a3f85b0c0565 (patch) | |
tree | f846443fdf7888583b4b0ff0ddd0be1be4b37df6 /arch/alpha/kernel/smp.c | |
parent | 831451ac4e44d3a20b581ce726ef1d1144373f7d (diff) |
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 'arch/alpha/kernel/smp.c')
0 files changed, 0 insertions, 0 deletions