Re: [PATCH RFC] x86 / CPU: Add cpu isolation flag for avoiding disturbance from aperfmperf IPI

[Konstantin Khlebnikov]

On 25.04.2019 14:45, Peter Zijlstra wrote:
> On Thu, Apr 25, 2019 at 01:46:51PM +0300, Konstantin Khlebnikov wrote:
> > Sensitive workloads like DPDK polling do not like any interrupts.
> >
> > This patch adds flag 'freq' for boot option 'isolcpu': isolcpu=freq,<cpus>.
> >
> > Users like show_cpuinfo() fallback to frequency from generic cpufreq
> > policy if arch-specific requesting method returns 0.
>
> Then don't touch that sysfs file?

What sysfs file?
I mean many applications read /proc/cpuinfo and this triggers IPI to all cpus.

> I really hate having an option for just this.

This could be generalized to 'isolate cpu from unnecessary IPI'.
Something like mm pagevec drain also could be avoided.