linux-kernel - Re: [PATCH v3 0/9] perf: Default use of build IDs and improvements

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Message-ID: <CAP-5=fWk=HFojgZi0eXCuBTc8WLJL1c6vMhow7xHfPmovXpxuQ@mail.gmail.com>
Date: Wed, 28 May 2025 11:58:13 -0700
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>, Kan Liang <kan.liang@...ux.intel.com>, 
	Athira Rajeev <atrajeev@...ux.ibm.com>, Kajol Jain <kjain@...ux.ibm.com>, 
	Li Huafei <lihuafei1@...wei.com>, "Steinar H. Gunderson" <sesse@...gle.com>, 
	James Clark <james.clark@...aro.org>, Stephen Brennan <stephen.s.brennan@...cle.com>, 
	Andi Kleen <ak@...ux.intel.com>, Dmitry Vyukov <dvyukov@...gle.com>, 
	Zhongqiu Han <quic_zhonhan@...cinc.com>, Yicong Yang <yangyicong@...ilicon.com>, 
	Krzysztof Łopatowski <krzysztof.m.lopatowski@...il.com>, 
	"Dr. David Alan Gilbert" <linux@...blig.org>, Zixian Cai <fzczx123@...il.com>, 
	Steve Clevenger <scclevenger@...amperecomputing.com>, 
	Thomas Falcon <thomas.falcon@...el.com>, Martin Liska <martin.liska@....com>, 
	Martin Liška <m.liska@...link.cz>, 
	Song Liu <song@...nel.org>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 0/9] perf: Default use of build IDs and improvements

On Wed, May 28, 2025 at 11:48 AM Arnaldo Carvalho de Melo
<acme@...nel.org> wrote:
>
> On Tue, May 27, 2025 at 01:48:43PM -0700, Ian Rogers wrote:
> > On Mon, Apr 28, 2025 at 2:34 PM Ian Rogers <irogers@...gle.com> wrote:
> > >
> > > Build ID mmap2 events have been available since Linux v5.12 and avoid
> > > certain races. Enable these by default as discussed in:
> > > https://lore.kernel.org/linux-perf-users/CAP-5=fXP7jN_QrGUcd55_QH5J-Y-FCaJ6=NaHVtyx0oyNh8_-Q@mail.gmail.com/
> > >
> > > The dso_id is used to indentify a DSO that may change by being
> > > overwritten. The inode generation isn't present in /proc/pid/maps and
> > > so was already only optionally filled in. With build ID mmap events
> > > the other major, minor and inode varialbes aren't filled in. Change
> > > the dso_id implementation to make optional values explicit, rather
> > > than injecting a dso_id we want to improve it during find operations,
> > > add the buildid to the dso_id for sorting and so that matching fails
> > > when build IDs vary between DSOs.
> > >
> > > Mark the callchain for buildids and not just the sample IP, fixing
> > > missing DSOs.
> > >
> > > Fix sample__for_each_callchain_node to populate the map even when
> > > symbols aren't computed.
> > >
> > > Other minor bits of build_id clean up.
> > >
> > > v3: Ensure the struct build_id is initialized empty prior to use as
> > >     read paths may fail (Namhyung).
> > >
> > > v2: Make marking DSOs still the default even with the defaulted build
> > >     ID mmap. The command line option still disables this to avoid
> > >     regressions. Add callchain patches and jitdump fix.
> >
> > Ping. Thanks,
> > Ian
>
> ⬢ [acme@...lbx perf-tools-next]$        git am ./v3_20250428_irogers_perf_default_use_of_build_ids_and_improvements.mbx
> Applying: perf callchain: Always populate the addr_location map when adding IP
> Applying: perf build-id: Reduce size of "size" variable
> Applying: perf build-id: Truncate to avoid overflowing the build_id data
> Applying: perf build-id: Change sprintf functions to snprintf
> Applying: perf build-id: Mark DSO in sample callchains
> Applying: perf build-id: Ensure struct build_id is empty before use
> Applying: perf dso: Move build_id to dso_id
> Applying: perf jitdump: Directly mark the jitdump DSO
> Applying: perf record: Make --buildid-mmap the default
> error: patch failed: tools/perf/builtin-record.c:3349
> error: tools/perf/builtin-record.c: patch does not apply
> Patch failed at 0009 perf record: Make --buildid-mmap the default
> hint: Use 'git am --show-current-patch=diff' to see the failed patch
> hint: When you have resolved this problem, run "git am --continue".
> hint: If you prefer to skip this patch, run "git am --skip" instead.
> hint: To restore the original branch and stop patching, run "git am --abort".
> hint: Disable this message with "git config set advice.mergeConflict false"
> ⬢ [acme@...lbx perf-tools-next]$

Thanks, I'll send the rebase in v4. I saw you had a branch on
perf-tools-next.git.

Thanks,
Ian

> - Arnaldo