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

From: Konstantin Khlebnikov
Date: Thu Apr 25 2019 - 08:27:20 EST

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.