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

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Message-ID: <aDdaZ0TMA5kwZ-iV@x1>
Date: Wed, 28 May 2025 15:48:07 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ian Rogers <irogers@...gle.com>
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 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]$

- Arnaldo