linux-kernel - [PATCH v1 0/3] Fix and improve __maps__fixup_overlap_and

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Message-Id: <20240521165109.708593-1-irogers@google.com>
Date: Tue, 21 May 2024 09:51:06 -0700
From: Ian Rogers <irogers@...gle.com>
To: "Steinar H . Gunderson" <sesse@...gle.com>, Peter Zijlstra <peterz@...radead.org>, 
	Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 0/3] Fix and improve __maps__fixup_overlap_and_insert

Fix latent unlikely bugs in __maps__fixup_overlap_and_insert.

Improve __maps__fixup_overlap_and_insert's performance 21x in the case
of overlapping mmaps. sesse@...gle.com reported slowness opening
perf.data files from chromium where the files contained a large number
of overlapping mappings. Improve this case primarily by avoiding
unnecessary sorting.

Unscientific timing data processing a perf.data file with overlapping
mmap events from chromium:

Before:
real    0m9.856s
user    0m9.637s
sys     0m0.204s

After:
real    0m0.675s
user    0m0.454s
sys     0m0.196s

Tested with address/leak sanitizer, invariant checks and validating
the before and after output are identical.

Ian Rogers (3):
  perf maps: Fix use after free in __maps__fixup_overlap_and_insert
  perf maps: Reduce sorting for overlapping mappings
  perf maps: Add/use a sorted insert for fixup overlap and insert

 tools/perf/util/maps.c | 113 +++++++++++++++++++++++++++++++++--------
 1 file changed, 92 insertions(+), 21 deletions(-)

-- 
2.45.0.rc1.225.g2a3ae87e7f-goog