linux-kernel - Re: [PATCH v1 2/6] perf trace: Ignore thread hashing in summary

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Date: Wed, 14 Feb 2024 13:15:27 -0800
From: Ian Rogers <irogers@...gle.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Namhyung Kim <namhyung@...nel.org>, Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Oliver Upton <oliver.upton@...ux.dev>, 
	Yang Jihong <yangjihong1@...wei.com>, linux-kernel@...r.kernel.org, 
	linux-perf-users@...r.kernel.org, bpf@...r.kernel.org
Subject: Re: [PATCH v1 2/6] perf trace: Ignore thread hashing in summary

On Wed, Feb 14, 2024 at 10:27 AM Ian Rogers <irogers@...gle.com> wrote:
>
> On Wed, Feb 14, 2024 at 9:25 AM Arnaldo Carvalho de Melo
> <acme@...nel.org> wrote:
> >
> > On Tue, Feb 13, 2024 at 10:37:04PM -0800, Ian Rogers wrote:
> > > Commit 91e467bc568f ("perf machine: Use hashtable for machine
> > > threads") made the iteration of thread tids unordered. The perf trace
> > > --summary output sorts and prints each hash bucket, rather than all
> > > threads globally. Change this behavior by turn all threads into a
> > > list, sort the list by number of trace events then by tids, finally
> > > print the list. This also allows the rbtree in threads to be not
> > > accessed outside of machine.
> >
> > Can you please provide a refresh of the output that is changed by your patch?
>
> Hmm.. looks like perf trace record has broken and doesn't produce
> output in newer perfs. It works on 6.5 and so a bisect is necessary.

Bisect result:
```
9925495d96efc14d885ba66c5696f664fe0e663c is the first bad commit
commit 9925495d96efc14d885ba66c5696f664fe0e663c
Author: Ian Rogers <irogers@...gle.com>
Date:   Thu Sep 14 14:19:45 2023 -0700

   perf build: Default BUILD_BPF_SKEL, warn/disable for missing deps
..
https://lore.kernel.org/r/20230914211948.814999-3-irogers@google.com
```

Now to do the bisect with BUILD_BPF_SKEL=1 on each make.

Thanks,
Ian