From nobody Thu Dec 18 18:02:53 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3C2EF1E888; Mon, 29 Apr 2024 22:57:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714431460; cv=none; b=tV2H1OfK50FMZm0Fn4HsytjLCJ4y61Zj2hve1sjsDM7PZfAITYks3965PhHQO2HdFWKeBBzvnuzEP0rFJ/3127ssV/r1pMkiBYesn1Rt3NX3wW/mU72FSTodIjsxVadNqSX9cpXcTU4ryEDUkvlhyTAKaFsmYyfsM3G7uB54xN0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714431460; c=relaxed/simple; bh=WIYeIyuZMEic4wS0TYk6SanQeD6+R01+KLorHb/LgME=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=d5GDpLqgkWn7dDi7pZVXtTeNYu5N5vLDcjMPFHX2aWRJJpgBNIQsM6aMH23nFw93FEy0bleWqyXA4G+8KHkMnXnBeQfPe2HWTxz8ZkSE2ErwqGHTMUEdvjehvLwW3Sr8a3RMlNz/DbNJ2QuGgynu5oNt1WnQ03LHRA+PuIoyeZ4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FUinoZIO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FUinoZIO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66D4BC113CD; Mon, 29 Apr 2024 22:57:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714431459; bh=WIYeIyuZMEic4wS0TYk6SanQeD6+R01+KLorHb/LgME=; h=From:To:Cc:Subject:Date:From; b=FUinoZIOtEWv0U80gEnwGYCB2S4xw8/q9RAT8i2Tr5YapZIIaH9P6tRkDa78gHKAO xPkgYHLhBYnvtqn5uHSDJTsTM/usXe9tDi3vNE6C7/x1Aom5HghDXF89ttbFvJmKeE wjUODox83ePCmtnwHxsxt4Yx3fDiID5RwOd4vswRZHiCutwsRP1MWqkIc54S3NBqLR FEBgt7u3cDh9gNCW1GuFp8mpmZR0njgO/yHE/cUY2NolHLkFaQlICG5wOb/MUtm768 hjAJSIIVops1kh7wnbMwUffHVSC8PHSyt07J+hJekB+RvJAlRY3QdocClZFyR3CgDt UQ7qoP7MIFEJQ== From: Namhyung Kim To: Arnaldo Carvalho de Melo , Ian Rogers , Kan Liang Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org Subject: [PATCH] perf maps: Remove check_invariants() from maps__lock() Date: Mon, 29 Apr 2024 15:57:38 -0700 Message-ID: <20240429225738.1491791-1-namhyung@kernel.org> X-Mailer: git-send-email 2.44.0.769.g3c40516874-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" I found that the debug build was a lot slowed down by the maps lock code since it checks the invariants whenever it gets the pointer to the lock. This means it checks twice the invariants before and after the access. Instead, let's move the checking code within the lock area but after any modification and remove it from the read paths. This would remove (more than) the half of the maps lock overhead. The time for perf report with a huge data file (200k+ of MMAP2 events). Non-debug Before After --------- -------- -------- 2m 43s 6m 45s 4m 21s Signed-off-by: Namhyung Kim Reviewed-by: Ian Rogers --- tools/perf/util/maps.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c index 725300896f38..61eb742d91e3 100644 --- a/tools/perf/util/maps.c +++ b/tools/perf/util/maps.c @@ -211,11 +211,6 @@ void maps__set_unwind_libunwind_ops(struct maps *maps,= const struct unwind_libun =20 static struct rw_semaphore *maps__lock(struct maps *maps) { - /* - * When the lock is acquired or released the maps invariants should - * hold. - */ - check_invariants(maps); return &RC_CHK_ACCESS(maps)->lock; } =20 @@ -358,6 +353,7 @@ static int map__strcmp(const void *a, const void *b) static int maps__sort_by_name(struct maps *maps) { int err =3D 0; + down_write(maps__lock(maps)); if (!maps__maps_by_name_sorted(maps)) { struct map **maps_by_name =3D maps__maps_by_name(maps); @@ -384,6 +380,7 @@ static int maps__sort_by_name(struct maps *maps) maps__set_maps_by_name_sorted(maps, true); } } + check_invariants(maps); up_write(maps__lock(maps)); return err; } @@ -502,6 +499,7 @@ int maps__insert(struct maps *maps, struct map *map) =20 down_write(maps__lock(maps)); ret =3D __maps__insert(maps, map); + check_invariants(maps); up_write(maps__lock(maps)); return ret; } @@ -536,6 +534,7 @@ void maps__remove(struct maps *maps, struct map *map) { down_write(maps__lock(maps)); __maps__remove(maps, map); + check_invariants(maps); up_write(maps__lock(maps)); } =20 @@ -602,6 +601,7 @@ void maps__remove_maps(struct maps *maps, bool (*cb)(st= ruct map *map, void *data else i++; } + check_invariants(maps); up_write(maps__lock(maps)); } =20 @@ -942,6 +942,8 @@ int maps__copy_from(struct maps *dest, struct maps *par= ent) map__put(new); } } + check_invariants(dest); + up_read(maps__lock(parent)); up_write(maps__lock(dest)); return err; @@ -1097,6 +1099,7 @@ void maps__fixup_end(struct maps *maps) map__set_end(maps_by_address[n - 1], ~0ULL); =20 RC_CHK_ACCESS(maps)->ends_broken =3D false; + check_invariants(maps); =20 up_write(maps__lock(maps)); } @@ -1147,6 +1150,8 @@ int maps__merge_in(struct maps *kmaps, struct map *ne= w_map) map__start(kmaps_maps_by_address[first_after_]) >=3D map__end(new_map= )) { /* No overlap so regular insert suffices. */ int ret =3D __maps__insert(kmaps, new_map); + + check_invariants(kmaps); up_write(maps__lock(kmaps)); return ret; } @@ -1184,6 +1189,7 @@ int maps__merge_in(struct maps *kmaps, struct map *ne= w_map) map__zput(kmaps_maps_by_address[i]); =20 free(kmaps_maps_by_address); + check_invariants(kmaps); up_write(maps__lock(kmaps)); return 0; } --=20 2.44.0.769.g3c40516874-goog