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 B70552210C0; Fri, 20 Dec 2024 19:20:40 +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=1734722440; cv=none; b=kyw6Z3GOU3i0RiSFEtHtoWr4Q+DnS473ElPAdK4xXgyT+veKr5DbX0vG9TcldinvLLQYdN9UjtIYhKtscuiOTt4dM9FQGXPw6Ldwt5/kh+H56eNm1NBq5vRtMAyhsgXmVOMng8v5X4kPPMDO6dH3Xu0X+TX8wUSpsyTQ03KL32c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734722440; c=relaxed/simple; bh=8XbdBcK3RoQ29Q3VwBSaVOI51Tab2e3sofg0RlarLnk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YcFwd/tx6KKF9Ds1CDdUtoqyjfW39R2iB1K0qxx4p+xM7Yfbrfwz3nOY6yol31Uxg5MQ/kw5xZ4Mcp17LHQVhvbOA2ggHXlC086725AThTaG0E/bQ50vJY3Xcbnug5aDgwTuonqE9Js7veSot+W2lK66TZgnI3lSb4iSJZx9bLc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H++3vzxz; 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="H++3vzxz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 384F5C4CECD; Fri, 20 Dec 2024 19:20:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734722440; bh=8XbdBcK3RoQ29Q3VwBSaVOI51Tab2e3sofg0RlarLnk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=H++3vzxzY6lrc9JZ87oEZGsCSBoH2fPiwmDg/zOlK1d3G6zDy2tXm/wiNw5myOerx NvEEzKA6zbeZvNy9hXwePCGVHjR0B5uAW2K/tZ7ccwXsRxuzXSfnQWeomH7rY+Cs0U RomiXeA4uGcoCPLbeXbuhvZ2Sqboov9dBjeh4zy5P/EAdzZ9ezyG/zSG3nMiki+747 E5tSrKx+mYBjCfWBNz96lxv6HNOzTgwHguvASpWnpDUKEcr3lJxDZj8C3JbAWMyPYm WpA46tlvK5HIOnQrNKBT2RbqdlBa9AxKiacP61E4vDpxv2u0oBlYaQ8kSmIOjy1DLM 2n2mgFCIQ43+w== Date: Fri, 20 Dec 2024 16:20:37 -0300 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ian Rogers , Kan Liang , Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Andrii Nakryiko , Song Liu , bpf@vger.kernel.org, Stephane Eranian , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Kees Cook , Chun-Tse Shao Subject: Re: [PATCH v3 0/4] perf lock contention: Symbolize locks using slab cache names Message-ID: References: <20241220060009.507297-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@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: <20241220060009.507297-1-namhyung@kernel.org> On Thu, Dec 19, 2024 at 10:00:05PM -0800, Namhyung Kim wrote: > Hello, > > This is to support symbolization of dynamic locks using slab > allocator's metadata. The kernel support is merged to v6.13. > > It provides the new "kmem_cache" BPF iterator and "bpf_get_kmem_cache" > kfunc to get the information from an address. The feature detection is > done using BTF type info and it won't have any effect on old kernels. > > v3 changes) > > * fix build error with GEN_VMLINUX_H=1 (Arnaldo) Thanks, applied to perf-tools-next, - Arnaldo > * update comment to explain slab cache ID (Vlastimil) > * add Ian's Acked-by > > v2) https://lore.kernel.org/linux-perf-users/20241108061500.2698340-1-namhyung@kernel.org > > * don't use libbpf_get_error() (Andrii) > > v1) https://lore.kernel.org/linux-perf-users/20241105172635.2463800-1-namhyung@kernel.org > > With this change, it can show locks in a slab object like below. I > added "&" sign to distinguish them from global locks. > > # perf lock con -abl sleep 1 > contended total wait max wait avg wait address symbol > > 2 1.95 us 1.77 us 975 ns ffff9d5e852d3498 &task_struct (mutex) > 1 1.18 us 1.18 us 1.18 us ffff9d5e852d3538 &task_struct (mutex) > 4 1.12 us 354 ns 279 ns ffff9d5e841ca800 &kmalloc-cg-512 (mutex) > 2 859 ns 617 ns 429 ns ffffffffa41c3620 delayed_uprobe_lock (mutex) > 3 691 ns 388 ns 230 ns ffffffffa41c0940 pack_mutex (mutex) > 3 421 ns 164 ns 140 ns ffffffffa3a8b3a0 text_mutex (mutex) > 1 409 ns 409 ns 409 ns ffffffffa41b4cf8 tracepoint_srcu_srcu_usage (mutex) > 2 362 ns 239 ns 181 ns ffffffffa41cf840 pcpu_alloc_mutex (mutex) > 1 220 ns 220 ns 220 ns ffff9d5e82b534d8 &signal_cache (mutex) > 1 215 ns 215 ns 215 ns ffffffffa41b4c28 tracepoint_srcu_srcu_usage (mutex) > > The first two were from "task_struct" slab cache. It happened to > match with the type name of object but there's no guarantee. We need > to add type info to slab cache to resolve the lock inside the object. > Anyway, the third one has no dedicated slab cache and was allocated by > kmalloc. > > Those slab objects can be used to filter specific locks using -L or > --lock-filter option. (It needs quotes to avoid special handling in > the shell). > > # perf lock con -ab -L '&task_struct' sleep 1 > contended total wait max wait avg wait type caller > > 1 25.10 us 25.10 us 25.10 us mutex perf_event_exit_task+0x39 > 1 21.60 us 21.60 us 21.60 us mutex futex_exit_release+0x21 > 1 5.56 us 5.56 us 5.56 us mutex futex_exec_release+0x21 > > The code is available at 'perf/lock-slab-v3' branch in my tree > > git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git > > Thanks, > Namhyung > > > Namhyung Kim (4): > perf lock contention: Add and use LCB_F_TYPE_MASK > perf lock contention: Run BPF slab cache iterator > perf lock contention: Resolve slab object name using BPF > perf lock contention: Handle slab objects in -L/--lock-filter option > > tools/perf/builtin-lock.c | 39 ++++- > tools/perf/util/bpf_lock_contention.c | 140 +++++++++++++++++- > .../perf/util/bpf_skel/lock_contention.bpf.c | 95 +++++++++++- > tools/perf/util/bpf_skel/lock_data.h | 15 +- > tools/perf/util/bpf_skel/vmlinux/vmlinux.h | 8 + > tools/perf/util/lock-contention.h | 2 + > 6 files changed, 292 insertions(+), 7 deletions(-) > > -- > 2.47.1.613.gc27f4b7a9f-goog