From nobody Sun Feb 8 12:43:13 2026 Received: from mout02.posteo.de (mout02.posteo.de [185.67.36.66]) (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 E58F15914A for ; Mon, 11 Mar 2024 22:57:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.66 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710197833; cv=none; b=uH8wLIaH/0ApKQauozyJoqjELHYpLKcEuEKrwslxYPyeDTU1+ly6GBSczLWthHo85ktnos8vbuYuSFubqEj//pgTBTfv1DFQgGarwrV3my4JJfjE30p+IRVH0qbGo2MDSsU7+wopf73/kMCP8soAVIwVFIRa+PKeK9YSqLRpUZs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710197833; c=relaxed/simple; bh=tj9OXdwPc5R1uIG5Y754PbkvA6/O9POegUZKX17YnUI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=KnwF+dxbfKfg7vdgZC5OaP254pv+vQjdE5AIkdLODxW9FxIGemgTEBWcQ0bfOaLxGlDuTF/EdKmkG4MhRmuNUMXBqDoSDCJi7Jg0Mwigt3L5GYzBXs3Iw421MqQOxvaEJ73zQiqwaVUEmBN/cB8IKj1MzFkB9+u/BrUVXg7mS4g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.net; spf=pass smtp.mailfrom=posteo.net; dkim=pass (2048-bit key) header.d=posteo.net header.i=@posteo.net header.b=hA4zvyWp; arc=none smtp.client-ip=185.67.36.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=posteo.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=posteo.net header.i=@posteo.net header.b="hA4zvyWp" Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id DF948240105 for ; Mon, 11 Mar 2024 23:57:07 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1710197827; bh=tj9OXdwPc5R1uIG5Y754PbkvA6/O9POegUZKX17YnUI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version: Content-Transfer-Encoding:From; b=hA4zvyWpgvA44JZh9C1zQ9ncrOI1K+z7HxwBhj6nVSt5qS4bNkMAEBNF+VtluLKVh Rg/w4KRoToOmxUXLtk5fzmhq3uQLd0e6g6BzwGJeOD8sotVXoX+aWoOi3pM2ynf98E nvY4wWPDnJBzV4ujU2aUt1CAD2epEILjpVYIiFmpacBy6rQ33ZuOe9l8lF+oizccoO /2E6yI6C6deEFzfl4DylK+Cmj7R+qMPR9vuEq1Kwapr30SkTsGaqY78H4RoFA4Vefv ECsiPU6j59N6b9uTRLe/8nGKhBQUJKLFYdr18Mw59gT2F3gDKER1Qr4wlnqYQ3w//b Rk3xapT7LPbfg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4Ttsbd5kSNz9rxD; Mon, 11 Mar 2024 23:57:01 +0100 (CET) From: Anne Macedo To: Arnaldo Carvalho de Melo , Namhyung Kim Cc: Anne Macedo , Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] perf lock contention: skip traceiter functions Date: Mon, 11 Mar 2024 22:56:15 +0000 Message-Id: <20240311225617.179184-1-retpolanne@posteo.net> 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" The perf lock contention program currently shows the caller of the locks as __traceiter_contention_begin+0x??. This caller can be ignored, as it is from the traceiter itself. Instead, it should show the real callers for the locks. When fiddling with the --stack-skip parameter, the actual callers for the locks start to show up. However, just ignore the __traceiter_contention_begin and the __traceiter_contention_end symbols so the actual callers will show up. Before this patch is applied: sudo perf lock con -a -b -- sleep 3 contended total wait max wait avg wait type caller 8 2.33 s 2.28 s 291.18 ms rwlock:W __traceite= r_contention_begin+0x44 4 2.33 s 2.28 s 582.35 ms rwlock:W __traceite= r_contention_begin+0x44 7 140.30 ms 46.77 ms 20.04 ms rwlock:W __traceite= r_contention_begin+0x44 2 63.35 ms 33.76 ms 31.68 ms mutex trace_cont= ention_begin+0x84 2 46.74 ms 46.73 ms 23.37 ms rwlock:W __traceite= r_contention_begin+0x44 1 13.54 us 13.54 us 13.54 us mutex trace_cont= ention_begin+0x84 1 3.67 us 3.67 us 3.67 us rwsem:R __traceite= r_contention_begin+0x44 Before this patch is applied - using --stack-skip 5 sudo perf lock con --stack-skip 5 -a -b -- sleep 3 contended total wait max wait avg wait type caller 2 2.24 s 2.24 s 1.12 s rwlock:W do_epoll_w= ait+0x5a0 4 1.65 s 824.21 ms 412.08 ms rwlock:W do_exit+0x= 338 2 824.35 ms 824.29 ms 412.17 ms spinlock get_signal= +0x108 2 824.14 ms 824.14 ms 412.07 ms rwlock:W release_ta= sk+0x68 1 25.22 ms 25.22 ms 25.22 ms mutex cgroup_kn_= lock_live+0x58 1 24.71 us 24.71 us 24.71 us spinlock do_exit+0x= 44 1 22.04 us 22.04 us 22.04 us rwsem:R lock_mm_an= d_find_vma+0xb0 After this patch is applied: sudo ./perf lock con -a -b -- sleep 3 contended total wait max wait avg wait type caller 4 4.13 s 2.07 s 1.03 s rwlock:W release_ta= sk+0x68 2 2.07 s 2.07 s 1.03 s rwlock:R mm_update_= next_owner+0x50 2 2.07 s 2.07 s 1.03 s rwlock:W do_exit+0x= 338 1 41.56 ms 41.56 ms 41.56 ms mutex cgroup_kn_= lock_live+0x58 2 36.12 us 18.83 us 18.06 us rwlock:W do_exit+0x= 338 changes since v1: - consider trace_contention and __traceiter_contention functions as optional (i.e. check if sym is null to avoid segfault) changes since v0: - skip trace_contention functions - use sym->end instead of __traceiter_contention_end for text_end Signed-off-by: Anne Macedo --- tools/perf/util/machine.c | 21 +++++++++++++++++++++ tools/perf/util/machine.h | 2 +- 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 527517db3182..968f69364f9a 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -3266,6 +3266,18 @@ bool machine__is_lock_function(struct machine *machi= ne, u64 addr) =20 sym =3D machine__find_kernel_symbol_by_name(machine, "__lock_text_end", = &kmap); machine->lock.text_end =3D map__unmap_ip(kmap, sym->start); + + sym =3D machine__find_kernel_symbol_by_name(machine, "__traceiter_conten= tion_begin", &kmap); + if (sym) { + machine->traceiter.text_start =3D map__unmap_ip(kmap, sym->start); + machine->traceiter.text_end =3D map__unmap_ip(kmap, sym->end); + } + + sym =3D machine__find_kernel_symbol_by_name(machine, "trace_contention_b= egin", &kmap); + if (sym) { + machine->trace.text_start =3D map__unmap_ip(kmap, sym->start); + machine->trace.text_end =3D map__unmap_ip(kmap, sym->end); + } } =20 /* failed to get kernel symbols */ @@ -3280,5 +3292,14 @@ bool machine__is_lock_function(struct machine *machi= ne, u64 addr) if (machine->lock.text_start <=3D addr && addr < machine->lock.text_end) return true; =20 + /* traceiter functions currently don't have their own section + * but we consider them lock functions + */ + if (machine->traceiter.text_start <=3D addr && addr < machine->traceiter.= text_end) + return true; + + if (machine->trace.text_start <=3D addr && addr < machine->trace.text_end) + return true; + return false; } diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index e28c787616fe..4312f6db6de0 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -49,7 +49,7 @@ struct machine { struct { u64 text_start; u64 text_end; - } sched, lock; + } sched, lock, traceiter, trace; pid_t *current_tid; size_t current_tid_sz; union { /* Tool specific area */ --=20 2.39.2