Re: [PATCH v3 1/2] perf/core: Share an event with multiple cgroups

[Peter Zijlstra]

On Tue, Apr 20, 2021 at 01:34:40AM -0700, Stephane Eranian wrote:
> The sampling approach will certainly incur more overhead and be at
> risk of losing the ability to
> reconstruct the total counter per-cgroup, unless  you set the period
> for SW_CGROUP_SWITCHES to
> 1. But then, you run the risk of losing samples if the buffer is full
> or sampling is throtlled.
> In some scenarios, we believe the number of context switches between
> cgroup could be quite high (>> 1000/s).
> And on top you would have to add the processing of the samples to
> extract the counts per cgroup. That would require
> a synthesis on cgroup on perf record and some post-processing on perf
> report. We are interested in using the data live
> to make some policy decisions, so a counting approach with perf stat
> will always be best.

Can you please configure your MUA to sanely (re)flow text? The above
random line-breaks are *so* painful to read.