Messages in this thread | | | Date | Wed, 6 Jul 2022 17:51:03 +0800 | Subject | Re: [PATCH v4 0/7] sched/fair: improve scan efficiency of SIS | From | Abel Wu <> |
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Gentle ping
On 6/19/22 8:04 PM, Abel Wu Wrote: > The wakeup fastpath (select_idle_sibling or SIS) plays an important role > in maximizing the usage of cpu resources and can greatly affect overall > performance of the system. > > The SIS tries to find an idle cpu inside that LLC to place the woken-up > task. The cache hot cpus will be checked first, then other cpus of that > LLC (domain scan) if the hot ones are not idle. > > The domain scan works well under light workload by simply traversing > the cpus of the LLC due to lots of idle cpus can be available. But this > doesn’t scale well once the LLC gets bigger and the load increases, so > SIS_PROP was born to limit the scan cost. For now SIS_PROP just limits > the number of cpus to be scanned, but the way of how it scans is not > changed. > > This patchset introduces the SIS filter to help improving scan efficiency > when scan depth is limited. The filter only contains the unoccupied cpus, > and is updated during SMT level load balancing. It is expected that the > more overloaded the system is, the less cpus will be scanned. > > ... >
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