Messages in this thread | | | From | Rahul Gopakumar <> | Subject | Re: [Linux Kernel 5.13 GA] ESXi Performance regression | Date | Thu, 5 Aug 2021 14:33:52 +0000 |
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> sysctl_sched_wakeup_granularity's default value hasn't been touched since > 2009: > > 172e082a9111 ("sched: Re-tune the scheduler latency defaults to decrease worst-case latencies") > > and the automagic scaling (see kernel/sched/fair.c::update_sysctl()) hasn't > changed much either. > > What's likely to happen here is that you have a service in your distro (or > somesuch) tweaking those values and since the incriminated commit moves > those files to /sys/kernel/debug/sched/, said service doesn't do anything > anymore.
Hi Valentin,
In our testing, we use RHEL 8.1 distro. It looks like tuned daemon updates 15ms (per tuned virtual-guest profile) in /proc/sys/kernel/sched_wakeup_granularity_ns file during tuned's startup.
Now tuned daemon is not able to update the value as the commit moves those files to debugs and thus sched_wakeup_granularity_ns file remains with the default value.
Regards, Rahul Gopakumar, Performance Engineering, VMware, Inc.
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