Messages in this thread | | | Date | Sat, 24 Mar 2018 11:50:23 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH v3 1/2] x86, msr: allow rdmsr_safe_on_cpu() to schedule |
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On Sat, 24 Mar 2018, Ingo Molnar wrote: > * Eric Dumazet <edumazet@google.com> wrote: > > > I noticed high latencies caused by a daemon periodically reading > > various MSR on all cpus. KASAN kernels would see ~10ms latencies > > simply reading one MSR. Even without KASAN, sending IPI to CPU > > in deep sleep state or blocking hard IRQ in a a long section, > > then waiting for the answer can consume hundreds of usec. > > > > Converts rdmsr_safe_on_cpu() to use a completion instead > > of busy polling. > > > > Overall daemon cpu usage was reduced by 35 %, > > and latencies caused by msr_read() disappeared. > > What "daemon" is this and why is it reading MSRs?
Why? Just because it can ....
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