Re: perf top -p broken for multithreaded processes since 5.19

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Fri, Sep 02, 2022 at 05:50:22PM +0300, Adrian Hunter escreveu:
> On 2/09/22 17:46, Tomáš Trnka wrote:
> > Hello,
> > 
> > A bug in perf v5.19 and newer completely breaks monitoring multithreaded
> > processes using "perf top -p". The tool fails to start with "Failed to mmap
> > with 22 (Invalid argument)". It still seems to work fine on single-threaded
> > processes. "perf record" is also unaffected.
> 
> It has been reported here:
> 
> 	https://bugzilla.kernel.org/show_bug.cgi?id=216441

If I do:

⬢[acme@toolbox perf-urgent]$ git log -2
commit dfeb0bc60782471c293938e71b1a1117cfac2cb3 (HEAD -> perf/urgent)
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
Date:   Fri Sep 2 16:15:39 2022 -0300

    Revert "libperf evlist: Check nr_mmaps is correct"

    This reverts commit 4ce47d842d4c16c07b135b8a7975b8f0672bcc0e.

    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

commit 78cd283f6b8ab701cb35eafd5af8140560a88f16
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
Date:   Fri Sep 2 16:13:41 2022 -0300

    Revert "libperf evlist: Allow mixing per-thread and per-cpu mmaps"

    This reverts commit ae4f8ae16a07896403c90305d4b9be27f657c1fc.

    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
⬢[acme@toolbox perf-urgent]$

It works again, Tomáš can you please try doing this to see if this works
for you?

- Arnaldo