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| author | Peter Zijlstra <peterz@infradead.org> | 2013-07-04 12:56:46 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-07-23 12:22:06 +0200 |
| commit | 7d9ffa8961482232d964173cccba6e14d2d543b2 (patch) | |
| tree | 80fd615fb64b1bd82e0de0e5d1e8be2bae8cb06d /kernel/sched/fair.c | |
| parent | 62470419e993f8d9d93db0effd3af4296ecb79a5 (diff) | |
| download | lwn-7d9ffa8961482232d964173cccba6e14d2d543b2.tar.gz lwn-7d9ffa8961482232d964173cccba6e14d2d543b2.zip | |
sched: Micro-optimize the smart wake-affine logic
Smart wake-affine is using node-size as the factor currently, but the overhead
of the mask operation is high.
Thus, this patch introduce the 'sd_llc_size' percpu variable, which will record
the highest cache-share domain size, and make it to be the new factor, in order
to reduce the overhead and make it more reasonable.
Tested-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Tested-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/51D5008E.6030102@linux.vnet.ibm.com
[ Tidied up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 860063a8c849..f237437446e5 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3175,7 +3175,7 @@ static inline unsigned long effective_load(struct task_group *tg, int cpu, static int wake_wide(struct task_struct *p) { - int factor = nr_cpus_node(cpu_to_node(smp_processor_id())); + int factor = this_cpu_read(sd_llc_size); /* * Yeah, it's the switching-frequency, could means many wakee or |