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| author |   Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-09-01 10:34:35 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2009-09-04 10:09:54 +0200 |
| commit | a52bfd73589eaf88d9c95ad2c1de0b38a6b27972 (patch) | |
| tree | 33cee609a46624525abf1643d71d0fbc79e25f87 /kernel/sched.c | |
| parent | sched: Update the cpu_power sum during load-balance (diff) | |
| download | linux-dev-a52bfd73589eaf88d9c95ad2c1de0b38a6b27972.tar.xz linux-dev-a52bfd73589eaf88d9c95ad2c1de0b38a6b27972.zip | |
sched: Add smt_gain
The idea is that multi-threading a core yields more work
capacity than a single thread, provide a way to express a
static gain for threads.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Gautham R Shenoy <ego@in.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
LKML-Reference: <20090901083826.073345955@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index ecb4a47d4214..55112261027b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8523,9 +8523,15 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd) weight = cpumask_weight(sched_domain_span(sd)); /* * SMT siblings share the power of a single core. + * Usually multiple threads get a better yield out of + * that one core than a single thread would have, + * reflect that in sd->smt_gain. */ - if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) + if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { + power *= sd->smt_gain; power /= weight; + power >>= SCHED_LOAD_SHIFT; + } sg_inc_cpu_power(sd->groups, power); return; } |