From nobody Wed Feb 11 11:30:37 2026 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7B5B0155316 for ; Wed, 29 Jan 2025 00:25:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738110316; cv=none; b=f2X/fi9eLJtkM6raSz9U1vmn5KO8axXHhx+JL3431DLy0dXeLTiyiw+t1A48gnorPYywI4Ko8Na32CS5tCWpNCySVxBlRMJScgrTD7TKeMgnSbijbdAzVEq6lkN/WJ/cp/go0zxUm/9tGF3HCsq0CYQyZJxi3dSh/JlWCUZT6FE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738110316; c=relaxed/simple; bh=27Hu/QjNl2hArTosMTM15Ibs0q2pm4UaVBt0g8CsV+E=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=mMTWi5xbkilsP4O8tJpM9yDbGVLfGx5zjsI6F1HDPBULDAa7gsN9qSb9XA8zeL2tJnoz/UjZhQC0ZD8t7qJ6PwFoQsdtwxbZw9e2QA86ChL1re0N2aUEz4yM3GyR5q6txJ7N+L8jUL+fkf7iDpw9524wWxl4Y19PaTVOVhHDTuA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ctshao.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=EQI24tFL; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--ctshao.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="EQI24tFL" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-2ee8ced572eso12799332a91.0 for ; Tue, 28 Jan 2025 16:25:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1738110314; x=1738715114; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=PXeAr/W67pFJL0V452kTAWbs3WuQao1XWrD/nQMSmJk=; b=EQI24tFLn10xGvZ4HLHJC5iFHY4lTTa/aJSq3iHFTsK6Y2Va3jKT8g6l0uUyCWrzPE Vb22ShpdvAKlMH6Scf0uHctRtFx5y9nXM5MWY32JzrTTCFyDpPnqJQgdcXN8NYhemXlQ n4x0WCnkvp6xzOGAcIkmMtcahmBTr1H8TP4cPTmVBBK7XnblmrDklRVjv3MjoQ78emFA k56UYx+dpBt+DmBc5nZp4ysPhQ+E+Rt0jO39nRrXMxUdit/gQPYPB3k0sRwUfQXsOpJj UTSKrRCt1jaC5ld3XH3qMutgXP6lZimCaHKAxo3r7vpPzVD3Q88XB8kGsk5zG1e2OjQL 1sBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738110314; x=1738715114; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=PXeAr/W67pFJL0V452kTAWbs3WuQao1XWrD/nQMSmJk=; b=BEvQZR+8S+bIgF9KKgLIJo7tjv6IKT7T7nXG5nXAJgqBYbmoLVNza5WSPNT8aDfOqD ttDUpiliM75qJSzzHd1DsatoLuuNJr4F+iETO1lvAy6CQvne4VNjBAX2AzmJ4SqXahjy /+/w0DMrh7iqnCVObWRuAiO01tqKsiZ9aXYIJ547UbQfBQk1rbZxpYBgyQzD4WUp+ana Xy00LDQsR78K/A7ckOsRQ0Hgv6drXw9etG0bj33f3fEX8eGpLwHF0oBVYkGKYoXESNWW EyRM5jku2RPCD5quFmdSqTwpHlvLjTvaB1tGD3/8dWesb1phMS2aGbmKrdERRNSzvslA 0Cfg== X-Gm-Message-State: AOJu0Yw7jdtDxTABLfxo8AczNoccmB7+aJSOMJBtnIc0LdiW7cqZBDi1 isEOxGBPDEtQi1pHcBzDm9x2v16tsj57x3zd76h3D3iYuW/QSeoWchhUJs3GKHf3eAgCs/2bQO+ Ii2T51BNnpIdmgSk/HHZ57aI9Im0ol82gVHlCIaB0lMmf3iAXAgcA4aLb2fAKdNVxNRakyNOx7Z UX/ZgD3BMFR1w7m+tt2zX5v4pXo7D6L2E4qSAeXDyr X-Google-Smtp-Source: AGHT+IEXM93qHwaO7edPXGrECqoSkr/Auhvr+ArqW++XActsaTaaIYnOSH8wKgfjnEoeuuF4WQsk+oHQunQ= X-Received: from pfbbu11.prod.google.com ([2002:a05:6a00:410b:b0:725:3321:1f0c]) (user=ctshao job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:148c:b0:71e:21:d2d8 with SMTP id d2e1a72fcca58-72fd0bf3be7mr1616751b3a.7.1738110313779; Tue, 28 Jan 2025 16:25:13 -0800 (PST) Date: Tue, 28 Jan 2025 16:14:57 -0800 In-Reply-To: <20250129001905.619859-1-ctshao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250129001905.619859-1-ctshao@google.com> X-Mailer: git-send-email 2.48.1.262.g85cc9f2d1e-goog Message-ID: <20250129001905.619859-2-ctshao@google.com> Subject: [PATCH v3 1/5] perf lock: Add bpf maps for owner stack tracing From: Chun-Tse Shao To: linux-kernel@vger.kernel.org Cc: Chun-Tse Shao , peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, nathan@kernel.org, ndesaulniers@google.com, morbo@google.com, justinstitt@google.com, linux-perf-users@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a struct and few bpf maps in order to tracing owner stack. `struct owner_tracing_data`: Contains owner's pid, stack id, timestamp for when the owner acquires lock, and the count of lock waiters. `stack_buf`: Percpu buffer for retrieving owner stacktrace. `owner_stacks`: For tracing owner stacktrace to customized owner stack id. `owner_data`: For tracing lock_address to `struct owner_tracing_data` in bpf program. `owner_stat`: For reporting owner stacktrace in usermode. Signed-off-by: Chun-Tse Shao --- tools/perf/util/bpf_lock_contention.c | 16 +++++-- .../perf/util/bpf_skel/lock_contention.bpf.c | 42 ++++++++++++++++--- tools/perf/util/bpf_skel/lock_data.h | 7 ++++ 3 files changed, 57 insertions(+), 8 deletions(-) diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lo= ck_contention.c index fc8666222399..795e2374facc 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -131,9 +131,19 @@ int lock_contention_prepare(struct lock_contention *co= n) else bpf_map__set_max_entries(skel->maps.task_data, 1); =20 - if (con->save_callstack) - bpf_map__set_max_entries(skel->maps.stacks, con->map_nr_entries); - else + if (con->save_callstack) { + bpf_map__set_max_entries(skel->maps.stacks, + con->map_nr_entries); + if (con->owner) { + bpf_map__set_value_size(skel->maps.stack_buf, con->max_stack * sizeof(u= 64)); + bpf_map__set_key_size(skel->maps.owner_stacks, + con->max_stack * sizeof(u64)); + bpf_map__set_max_entries(skel->maps.owner_stacks, con->map_nr_entries); + bpf_map__set_max_entries(skel->maps.owner_data, con->map_nr_entries); + bpf_map__set_max_entries(skel->maps.owner_stat, con->map_nr_entries); + skel->rodata->max_stack =3D con->max_stack; + } + } else bpf_map__set_max_entries(skel->maps.stacks, 1); =20 if (target__has_cpu(target)) { diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/ut= il/bpf_skel/lock_contention.bpf.c index 6533ea9b044c..b4961dd86222 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -19,13 +19,37 @@ #define LCB_F_PERCPU (1U << 4) #define LCB_F_MUTEX (1U << 5) =20 -/* callstack storage */ + /* buffer for owner stacktrace */ struct { - __uint(type, BPF_MAP_TYPE_STACK_TRACE); + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); __uint(key_size, sizeof(__u32)); __uint(value_size, sizeof(__u64)); - __uint(max_entries, MAX_ENTRIES); -} stacks SEC(".maps"); + __uint(max_entries, 1); +} stack_buf SEC(".maps"); + +/* a map for tracing owner stacktrace to owner stack id */ +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(key_size, sizeof(__u64)); // owner stacktrace + __uint(value_size, sizeof(__u64)); // owner stack id + __uint(max_entries, 1); +} owner_stacks SEC(".maps"); + +/* a map for tracing lock address to owner data */ +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(key_size, sizeof(__u64)); // lock address + __uint(value_size, sizeof(struct owner_tracing_data)); + __uint(max_entries, 1); +} owner_data SEC(".maps"); + +/* a map for contention_key (stores owner stack id) to contention data */ +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(key_size, sizeof(struct contention_key)); + __uint(value_size, sizeof(struct contention_data)); + __uint(max_entries, 1); +} owner_stat SEC(".maps"); =20 /* maintain timestamp at the beginning of contention */ struct { @@ -43,6 +67,14 @@ struct { __uint(max_entries, 1); } tstamp_cpu SEC(".maps"); =20 +/* callstack storage */ +struct { + __uint(type, BPF_MAP_TYPE_STACK_TRACE); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(__u64)); + __uint(max_entries, MAX_ENTRIES); +} stacks SEC(".maps"); + /* actual lock contention statistics */ struct { __uint(type, BPF_MAP_TYPE_HASH); @@ -143,6 +175,7 @@ const volatile int needs_callstack; const volatile int stack_skip; const volatile int lock_owner; const volatile int use_cgroup_v2; +const volatile int max_stack; =20 /* determine the key of lock stat */ const volatile int aggr_mode; @@ -466,7 +499,6 @@ int contention_end(u64 *ctx) return 0; need_delete =3D true; } - duration =3D bpf_ktime_get_ns() - pelem->timestamp; if ((__s64)duration < 0) { __sync_fetch_and_add(&time_fail, 1); diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_ske= l/lock_data.h index c15f734d7fc4..15f5743bd409 100644 --- a/tools/perf/util/bpf_skel/lock_data.h +++ b/tools/perf/util/bpf_skel/lock_data.h @@ -3,6 +3,13 @@ #ifndef UTIL_BPF_SKEL_LOCK_DATA_H #define UTIL_BPF_SKEL_LOCK_DATA_H =20 +struct owner_tracing_data { + u32 pid; // Who has the lock. + u32 count; // How many waiters for this lock. + u64 timestamp; // The time while the owner acquires lock and contention i= s going on. + s32 stack_id; // Identifier for `owner_stat`, which stores as value in `o= wner_stacks` +}; + struct tstamp_data { u64 timestamp; u64 lock; --=20 2.48.1.262.g85cc9f2d1e-goog