[lkml]   [2018]   [Mar]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v3 1/2] x86, msr: allow rdmsr_safe_on_cpu() to schedule

* Eric Dumazet <> 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?



 \ /
  Last update: 2018-03-24 09:10    [W:0.132 / U:1.228 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site