From mboxrd@z Thu Jan 1 00:00:00 1970 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 0FBAC134428; Thu, 21 Mar 2024 19:58:20 +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=1711051101; cv=none; b=OrXKi/mC2AojAYcDJz9wqn4AQ9TY1TS6TP5e1dtN1rWuGXDw3+EqK0KsrBWxV7eFP4fj81fDYHNHtfLyEBjp5Oju576ARinqmxt/XHU/rFEBm+h4pj8Rrd6fx6HE/1c7NRi7fk4RW62Rk+FFmdP716WrrWMA2klcdbXdHh9VVkQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711051101; c=relaxed/simple; bh=412A9G1xvc9KWN8uYFJK6xoGGzzP/mRkZgKkvJrAdPU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=U3nq50PjdGvxJrzMZPOsCJsK+EvFS+VP9QvSu460q2YP7vOiAaKPq9vhrSBjauiSxSlHT3O1nbWFbB/qGqHBx+Td/jECJQqoS1VYwYfi+2eTeL+NLL1izFGI4eoauTV/XId+972clobwEWv1RNX4NpwO6o2CB0nrnSc/VtHwiWA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Bswh3M17; 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="Bswh3M17" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 04026C433C7; Thu, 21 Mar 2024 19:58:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711051100; bh=412A9G1xvc9KWN8uYFJK6xoGGzzP/mRkZgKkvJrAdPU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Bswh3M17MUp9NQTSHevNoVHvLBea911+J3WRyO6SnDRPv4B8eJ3uiN9zMYDSKXehA Tz4lZ6s0NbImA5YLC0fkP4atBLp8SPFvtmS4Lx/0iD0rzrnKUQKGoBnFtY5GXXxKCE ifDxFRV9O5SW6lrortJjcYs9P4pykL/tEsP7JfGbWN4PdenQ0bbjEOEz956eQAiI1m reXbU9812uUEb3QA2rnfFXPLRlhOLtGgeJaL5vfkwAASKWYY5evR7p82rjttz5Oh3S XcmmuElVLQDzeZu8JeCv+FDJvW0TOhoAniYgY+TWrLCzn4vSLk1TEE0qD+yeXrE6Ln 6+yFqzk8Uq+/w== Date: Thu, 21 Mar 2024 16:58:17 -0300 From: Arnaldo Carvalho de Melo To: Anne Macedo Cc: Namhyung Kim , 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: Re: [PATCH v4] perf lock contention: skip traceiter functions Message-ID: References: <20240319143629.3422590-1-retpolanne@posteo.net> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240319143629.3422590-1-retpolanne@posteo.net> Now lemme nitpick a bit, and I'll do it myself while processing the patch, some are from my days sending patches to Ingo and from his requests it become second nature, others I do to further clarify the text: And here is the reason for top posting, the first request is about the subject line: Subject: [PATCH v4] perf lock contention: skip traceiter functions Becomes: Subject: [PATCH v4] perf lock contention: Trim backtrace by skipping traceiter functions Please make it so that after the component the one line summary starts with a capital letter and packs as much info as possible. On Tue, Mar 19, 2024 at 02:36:26PM +0000, Anne Macedo wrote: > The perf lock contention program currently shows the caller of the locks I try to make the sub (sub) command stand out by single quoting it: The 'perf lock contention' program currently shows the caller of the locks What follows is great, nice description, before/after. Thanks, testing it now on x86_64 and aarch64, will apply it then. - Arnaldo > 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 __traceiter_contention_begin+0x44 > 4 2.33 s 2.28 s 582.35 ms rwlock:W __traceiter_contention_begin+0x44 > 7 140.30 ms 46.77 ms 20.04 ms rwlock:W __traceiter_contention_begin+0x44 > 2 63.35 ms 33.76 ms 31.68 ms mutex trace_contention_begin+0x84 > 2 46.74 ms 46.73 ms 23.37 ms rwlock:W __traceiter_contention_begin+0x44 > 1 13.54 us 13.54 us 13.54 us mutex trace_contention_begin+0x84 > 1 3.67 us 3.67 us 3.67 us rwsem:R __traceiter_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_wait+0x5a0 > 4 1.65 s 824.21 ms 412.08 ms rwlock:W do_exit+0x338 > 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_task+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+0x44 > 1 22.04 us 22.04 us 22.04 us rwsem:R lock_mm_and_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_task+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+0x338 > 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+0x338 > > changes since v3: > > - remove dummy value and assume machine->traceiter and machine->trace > have zero address > > changes since v2: > > - add dummy value to machine->traceiter and machine->trace to make > necessary checks, fixing possible null pointer access > > 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 | 24 ++++++++++++++++++++++++ > tools/perf/util/machine.h | 2 +- > 2 files changed, 25 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > index 527517db3182..5eb9044bc223 100644 > --- a/tools/perf/util/machine.c > +++ b/tools/perf/util/machine.c > @@ -3266,6 +3266,17 @@ bool machine__is_lock_function(struct machine *machine, u64 addr) > > sym = machine__find_kernel_symbol_by_name(machine, "__lock_text_end", &kmap); > machine->lock.text_end = map__unmap_ip(kmap, sym->start); > + > + sym = machine__find_kernel_symbol_by_name(machine, "__traceiter_contention_begin", &kmap); > + if (sym) { > + machine->traceiter.text_start = map__unmap_ip(kmap, sym->start); > + machine->traceiter.text_end = map__unmap_ip(kmap, sym->end); > + } > + sym = machine__find_kernel_symbol_by_name(machine, "trace_contention_begin", &kmap); > + if (sym) { > + machine->trace.text_start = map__unmap_ip(kmap, sym->start); > + machine->trace.text_end = map__unmap_ip(kmap, sym->end); > + } > } > > /* failed to get kernel symbols */ > @@ -3280,5 +3291,18 @@ bool machine__is_lock_function(struct machine *machine, u64 addr) > if (machine->lock.text_start <= addr && addr < machine->lock.text_end) > return true; > > + /* traceiter functions currently don't have their own section > + * but we consider them lock functions > + */ > + if (machine->traceiter.text_start != 0) { > + if (machine->traceiter.text_start <= addr && addr < machine->traceiter.text_end) > + return true; > + } > + > + if (machine->trace.text_start != 0) { > + if (machine->trace.text_start <= 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 */ > -- > 2.39.2 >