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authorPeter Zijlstra <peterz@infradead.org>2013-01-22 13:09:13 +0530
committerGleb Natapov <gleb@redhat.com>2013-01-29 15:38:37 +0200
commit7b270f609982f68f2433442bf167f735e7364b06 (patch)
tree07430a425125c1938fad3befc6debec667310ec4 /virt
parentc7c9c56ca26f7b9458711b2d78b60b60e0d38ba7 (diff)
downloadvexpress-lsk-7b270f609982f68f2433442bf167f735e7364b06.tar.gz
sched: Bail out of yield_to when source and target runqueue has one task
In case of undercomitted scenarios, especially in large guests yield_to overhead is significantly high. when run queue length of source and target is one, take an opportunity to bail out and return -ESRCH. This return condition can be further exploited to quickly come out of PLE handler. (History: Raghavendra initially worked on break out of kvm ple handler upon seeing source runqueue length = 1, but it had to export rq length). Peter came up with the elegant idea of return -ESRCH in scheduler core. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Raghavendra, Checking the rq length of target vcpu condition added.(thanks Avi) Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Acked-by: Andrew Jones <drjones@redhat.com> Tested-by: Chegu Vinod <chegu_vinod@hp.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'virt')
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