Re: [RFC PATCH v1 0/3] Retirement latency perf stat support

[Ian Rogers]

On Thu, Apr 25, 2024 at 3:34 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> Support 'R' as a retirement latency modifier on events. When present
> the evsel will fork perf record and perf report commands, parsing the
> perf report output as the count value. The intent is to do something
> similar to Weilin's series:
> https://lore.kernel.org/lkml/20240402214436.1409476-1-weilin.wang@xxxxxxxxx/
>
> While the 'R' and the retirement latency are Intel specific, in the
> future I can imagine more evsel like commands that require child
> processes. We can make the logic more generic at that point.
>
> The code is untested on hardware that supports retirement latency, and
> with metrics with retirement latency in them. The record is also of
> sleep and various things need tweaking but I think v1 is good enough
> for people to give input.
>
> The first patch stops opening a dummy event for tool events. I came
> across this while looking into the issue and we can likely just pick
> it first. I kept it in the series for cleanliness sake.
>
> The code has benefitted greatly from Weilin's work and Namhyung's
> great review input.

I forgot to mention this is based on the tmp.perf-tools-next branch
due to the recent parse events clean ups that have already landed
there:
https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/log/?h=tmp.perf-tools-next

Thanks,
Ian

> Ian Rogers (3):
>   perf evsel: Don't open tool events
>   perf parse-events: Add a retirement latency modifier
>   perf evsel: Add retirement latency event support
>
>  tools/perf/util/evsel.c        | 186 ++++++++++++++++++++++++++++++++-
>  tools/perf/util/evsel.h        |   4 +
>  tools/perf/util/parse-events.c |   2 +
>  tools/perf/util/parse-events.h |   1 +
>  tools/perf/util/parse-events.l |   3 +-
>  5 files changed, 192 insertions(+), 4 deletions(-)
>
> --
> 2.44.0.769.g3c40516874-goog
>