linux-kernel - Re: [PATCH v4 0/6] Avoid parsing tracepoint format just for id

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Message-ID: <Zy-WM779rMwczlj_@google.com>
Date: Sat, 9 Nov 2024 09:04:51 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...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>,
	Kan Liang <kan.liang@...ux.intel.com>,
	Athira Jajeev <atrajeev@...ux.vnet.ibm.com>,
	James Clark <james.clark@...aro.org>,
	Dominique Martinet <asmadeus@...ewreck.org>,
	Yang Li <yang.lee@...ux.alibaba.com>,
	Colin Ian King <colin.i.king@...il.com>,
	Yang Jihong <yangjihong@...edance.com>,
	"Steinar H. Gunderson" <sesse@...gle.com>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Ilkka Koskinen <ilkka@...amperecomputing.com>,
	Ze Gao <zegao2021@...il.com>, Weilin Wang <weilin.wang@...el.com>,
	Ben Gainey <ben.gainey@....com>,
	zhaimingbing <zhaimingbing@...s.chinamobile.com>,
	Zixian Cai <fzczx123@...il.com>, Andi Kleen <ak@...ux.intel.com>,
	Paran Lee <p4ranlee@...il.com>,
	Thomas Falcon <thomas.falcon@...el.com>,
	linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
	"Steven Rostedt (Google)" <rostedt@...dmis.org>
Subject: Re: [PATCH v4 0/6] Avoid parsing tracepoint format just for id

On Sat, Nov 09, 2024 at 08:26:20AM -0800, Ian Rogers wrote:
> On Fri, Nov 8, 2024 at 10:45 PM Namhyung Kim <namhyung@...nel.org> wrote:
> > On Fri, Nov 08, 2024 at 10:47:45AM -0800, Ian Rogers wrote:
> > > Ian Rogers (6):
> > >   tool api fs: Correctly encode errno for read/write open failures
> > >   perf trace-event: Constify print arguments
> > >   perf trace-event: Always build trace-event-info.c
> > >   perf evsel: Add/use accessor for tp_format
> > >   perf evsel: Allow evsel__newtp without libtraceevent
> > >   perf tests: Enable tests disabled due to tracepoint parsing
> >
> > After applying this series, I'm seeing some test failures.  But I don't
> > understand why it affects non-tracepoint events though.
> >
> >   $ sudo ./perf test -v pipe
> >   --- start ---
> >   test child forked, pid 3036123
> >    1bde35-1bdecc l noploop
> >   perf does have symbol 'noploop'
> >
> >   Record+report pipe test
> >   [ perf record: Woken up 1 times to write data ]
> >   [ perf record: Captured and wrote 0.210 MB - ]
> >   [ perf record: Woken up 2 times to write data ]
> >   [ perf record: Captured and wrote 0.517 MB - ]
> >   [ perf record: Woken up 2 times to write data ]
> >   [ perf record: Captured and wrote 0.516 MB - ]
> >   Record+report pipe test [Success]
> >
> >   Inject -B build-ids test
> >   0xa5c [0x17a4]: failed to process type: 80
> >   Error:
> >   failed to process sample
> >   Inject build-ids test [Failed - cannot find noploop function in pipe #1]
> >
> >   Inject -b build-ids test
> >   0xa5c [0x17a4]: failed to process type: 80
> >   Error:
> >   failed to process sample
> >   Inject build-ids test [Failed - cannot find noploop function in pipe #1]
> >
> >   Inject --buildid-all build-ids test
> >   0xa5c [0x17a4]: failed to process type: 80
> >   Error:
> >   failed to process sample
> >   Inject build-ids test [Failed - cannot find noploop function in pipe #1]
> >
> >   Inject --mmap2-buildid-all build-ids test
> >   0xa5c [0x17a4]: failed to process type: 80
> >   Error:
> >   failed to process sample
> >   Inject build-ids test [Failed - cannot find noploop function in pipe #1]
> >   ---- end(-1) ----
> >    84: perf pipe recording and injection test                          : FAILED!
> >
> >   $ sudo ./perf test -v Zstd
> >   --- start ---
> >   test child forked, pid 3036097
> >   Collecting compressed record file:
> >   500+0 records in
> >   500+0 records out
> >   256000 bytes (256 kB, 250 KiB) copied, 0.00169127 s, 151 MB/s
> >   [ perf record: Woken up 1 times to write data ]
> >   [ perf record: Captured and wrote 0.032 MB /tmp/perf.data.KBo, compressed (original 0.004 MB, ratio is 3.324) ]
> >   Checking compressed events stats:
> >   Couldn't decompress data
> >   0x7ca8 [0x4f2]: failed to process type: 81 [Operation not permitted]
> >   Error:
> >   failed to process sample
> >   ---- end(-1) ----
> >    86: Zstd perf.data compression/decompression                        : FAILED!
> >
> > Thanks,
> > Namhyung
> 
> I'm not able to reproduce:
> ```
> $ git log --oneline |head
> a59bca6eb0a6 perf test: Add a runs-per-test flag
> 0d0c002eb45c perf tests: Enable tests disabled due to tracepoint parsing
> 4b8f5c9dfbda perf evsel: Allow evsel__newtp without libtraceevent
> 7f57057c7884 perf evsel: Add/use accessor for tp_format
> c27d357d2d4c perf trace-event: Always build trace-event-info.c
> 20bf7a2cd68a perf trace-event: Constify print arguments
> f18b07ee2af1 tool api fs: Correctly encode errno for read/write open failures
> ...
> $ sudo /tmp/perf/perf test -r 10 Zstd pipe -v
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 84: perf pipe recording and injection test                          : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> 86: Zstd perf.data compression/decompression                        : Ok
> ```
> Similarly not as root or if runs-per-test is 100.
> 
> Agreed that the changes are for tracepoints and these tests aren't for
> tracepoints, so an interaction wouldn't be expected. If you have a
> reliable reproduction perhaps you can bisect it.

it says:

9c10de391840a35ab095b65e9a5c4fad0ac52068 is the first bad commit
commit 9c10de391840a35ab095b65e9a5c4fad0ac52068 (HEAD)
Author: Ian Rogers <irogers@...gle.com>
Date:   Fri Nov 8 10:47:46 2024 -0800

    tool api fs: Correctly encode errno for read/write open failures
    
    Switch from returning -1 to -errno so that callers can determine types
    of failure.
    
    Signed-off-by: Ian Rogers <irogers@...gle.com>
    Acked-by: Arnaldo Carvalho de Melo <acme@...hat.com>

 tools/lib/api/fs/fs.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Thanks,
Namhyung