Messages in this thread | | | Date | Sat, 24 Mar 2018 09:09:46 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH v3 1/2] x86, msr: allow rdmsr_safe_on_cpu() to schedule |
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* 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?
Thanks,
Ingo
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