Messages in this thread | | | Date | Thu, 31 Oct 2019 10:19:04 +0000 | From | Mel Gorman <> | Subject | Re: [PATCH] sched/fair: Make sched-idle cpu selection consistent throughout |
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On Thu, Oct 31, 2019 at 02:42:03PM +0530, Viresh Kumar wrote: > On Wed, 30 Oct 2019 at 22:17, Mel Gorman <mgorman@suse.de> wrote: > > > As the patch stands, I think a fork-intensive workload where each > > process is doing small amounts of work will suffer from overloading > > domains and have variable performance depending on how quickly the load > > balancer reacts. > > Just wanted to clarify this slightly in case it is confusing. Once a > newly forked > (non SCHED_IDLE) task gets placed on a sched-idle CPU, it won't remain > sched-idle anymore and we will again start looking for a fully idle CPU. So, > we won't put everything on a small set of CPUs, but just one SCHED_NORMAL > task on a CPU unless we are out of idle CPUs. > > Do you have some specific test in mind which I can run to test this ? >
Nothing in particular. git test suite for the basic fork-intensive case (mmtests config workload-shellscripts), something fork-intensive but relatively short-lived like a kernel build scaling the number of build jobs (mmtests config config-workload-kerndevel), something fairly basic that scales number of running jobs and relatively long-lived like tbench (mmtests config config-network-tbench). The ideal of course is that you wrote the patch based on an observed problem that you decided to fix.
-- Mel Gorman SUSE Labs
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