From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (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 B1B6C29347C for ; Thu, 24 Apr 2025 19:58:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745524733; cv=none; b=Cu5d8OEgqpYFvDC+X5ZU1i4hPgq7pyXfvsMg6mH/KN+gGD8irVHKkY/Qz036KMnWXBwCHieFYdEaNYyy7cB5nz136Fwi2VULpljQ5Htk5/DIL29D34KRIYSGl71/bjBZw3v5G3Ma49+jPTN7UmmKW7H3EJcGoWhBgM7ReAHCv8M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745524733; c=relaxed/simple; bh=3mET9+njEz0Qqs0rjagQZqg2H0OJF9kLeZvRZQFAVGo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=sKzoucQqnr3EBkCa/nucy+SHtNE5cujjInPRObkm9ofe1QUeDdln9v1cBL2NIQ9RN4SGPWbKXqY9nhRwHDP0OwXpLTVr0/vUgDnDIy7MFI+OKd9Wl7S69ctlwGja8ZmZ+QQWfaUbul3kk2MlQMdCTuPA1+y65vZeh7JQtyzq43Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=3XTlBtxF; arc=none smtp.client-ip=209.85.216.73 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--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="3XTlBtxF" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-2ff798e8c3bso1105613a91.2 for ; Thu, 24 Apr 2025 12:58:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1745524731; x=1746129531; darn=vger.kernel.org; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=FsW7ntgrEiteL6+NRyYkKnb+c0cF8to6DMFvVFkK9wk=; b=3XTlBtxFMYyhKKjP2GYgKESbwCgAI3i1JyuuVtXoqI9AIRtXex9dVMCVG4eRku+6OX J31Fyjz6XcYCHF5Fi4glC5ghyP/jZTrKAsNXFKapokHBCxBQ9hRNrNNeAaYJJlHgwqii RiAkvtL4ZgajJlvSJYn5cm/rN8lc0QAX2M+VEHbzrLCvEA859Ra1RjBJ911sVnT2J4Rl gaPpmd/27AgMgJlDm2FCw6VKly+kyKuNH25px8fpOtCmVYdBsdpOvZWhUidXCB+GQmEE PT7ciKT3FmJOdhEoo1jQ5rbTuPwQMETUgexU7fHRK5o2V3wzVzg3uN+0SwzW48Jps4UU d57w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745524731; x=1746129531; h=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=FsW7ntgrEiteL6+NRyYkKnb+c0cF8to6DMFvVFkK9wk=; b=kVMxmM88zRUWpRy5Rwb9lSjpL2OqIaVzEGciB70v6bKajuxO74bB3yz7CwYf7UFc9F PyEm2axpTaCrwt90Y569SIb+AKA0U9ZLGgeS1V6lRM5hYeyVP2Ptdr6PsnV/q3IrxeBw eAKcCbkVyBJBjP3yAFnAGKsw2tAwXUHgvATpwexR9LvXP8lULqcytbr0zHZ1bpXP3MSy WgVpfcU+aC7ErNUiP76waJxZ3ocByP8TYxEQ/uq9jRxA9bst/mTc9iHUV5wi/UCiEHhz tMKR5JpX/83f0urQwwNyzmo3RZOIPZ0LC1nefsmZRdQDaXihznlmEIS1jq5Aq412ckEB NmfA== X-Forwarded-Encrypted: i=1; AJvYcCXIvqXHcN87A1EnO6rjEgLaO3l34L1GFlr9SmlQImGoKlQlP/upntr1QMbPywMAMJJLz4ItwYHTPhgwy2c=@vger.kernel.org X-Gm-Message-State: AOJu0YwGmk2HHlgyNxFdXcYIYNVRYXsnTt8bjx0RlSd+WbFZDQdY2VQM fCdGpKwQM99UQMYm0nG5k7/8I715ZSllu8MyZP+WeAojj9fyrVagnoizM1PHJHcDIWRLWLcdtAH l1tWw/Q== X-Google-Smtp-Source: AGHT+IF61i443moqQRGbCyMTbCxXjQRC0vDLWqpkI7uiwvfyhgS5AvqN7qVyEWF4SUVt4tzWu/5uC98s2k/Q X-Received: from pjkk11.prod.google.com ([2002:a17:90b:57eb:b0:2fa:2661:76ac]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90a:da90:b0:2fa:f8d:65de with SMTP id 98e67ed59e1d1-309f56c67c7mr997471a91.22.1745524730623; Thu, 24 Apr 2025 12:58:50 -0700 (PDT) Date: Thu, 24 Apr 2025 12:58:31 -0700 In-Reply-To: <20250424195831.1767457-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250424195831.1767457-1-irogers@google.com> X-Mailer: git-send-email 2.49.0.850.g28803427d3-goog Message-ID: <20250424195831.1767457-9-irogers@google.com> Subject: [PATCH v2 8/8] perf record: Make --buildid-mmap the default From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , Athira Rajeev , Kajol Jain , Li Huafei , "Steinar H. Gunderson" , James Clark , Stephen Brennan , Andi Kleen , Dmitry Vyukov , Zhongqiu Han , Yicong Yang , "=?UTF-8?q?Krzysztof=20=C5=81opatowski?=" , "Dr. David Alan Gilbert" , Zixian Cai , Steve Clevenger , Thomas Falcon , Martin Liska , "=?UTF-8?q?Martin=20Li=C5=A1ka?=" , Song Liu , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Support for build IDs in mmap2 perf events has been present since Linux v5.12: https://lore.kernel.org/lkml/20210219194619.1780437-1-acme@kernel.org/ Build ID mmap events don't avoid the need to inject build IDs for DSO touched by samples as the build ID cache is populated by perf record. They can avoid some cases of symbol mis-resolution caused by the file system changing from when a sample occurred and when the DSO is sought. To disable build ID scanning Unlike the --buildid-mmap option, this doesn't disable the build ID cache but it does disable the processing of samples looking for DSOs to inject build IDs for. To disable the build ID cache the -B (--no-buildid) option should be used. Making this option the default was raised on the list in: https://lore.kernel.org/linux-perf-users/CAP-5=fXP7jN_QrGUcd55_QH5J-Y-FCaJ6=NaHVtyx0oyNh8_-Q@mail.gmail.com/ Signed-off-by: Ian Rogers --- tools/perf/builtin-record.c | 33 +++++++++++++++++++----------- tools/perf/util/symbol_conf.h | 2 +- tools/perf/util/synthetic-events.c | 16 +++++++-------- 3 files changed, 30 insertions(+), 21 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index ba20bf7c011d..7b64013ba8c0 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -169,6 +169,7 @@ struct record { bool no_buildid_cache_set; bool buildid_all; bool buildid_mmap; + bool buildid_mmap_set; bool timestamp_filename; bool timestamp_boundary; bool off_cpu; @@ -1795,6 +1796,7 @@ record__finish_output(struct record *rec) data->dir.files[i].size = lseek(data->dir.files[i].fd, 0, SEEK_CUR); } + /* Buildid scanning disabled or build ID in kernel and synthesized map events. */ if (!rec->no_buildid) { process_buildids(rec); @@ -2966,6 +2968,8 @@ static int perf_record_config(const char *var, const char *value, void *cb) rec->no_buildid = true; else if (!strcmp(value, "mmap")) rec->buildid_mmap = true; + else if (!strcmp(value, "no-mmap")) + rec->buildid_mmap = false; else return -1; return 0; @@ -3349,6 +3353,7 @@ static struct record record = { .ctl_fd_ack = -1, .synth = PERF_SYNTH_ALL, }, + .buildid_mmap = true, }; const char record_callchain_help[] = CALLCHAIN_RECORD_HELP @@ -3514,8 +3519,8 @@ static struct option __record_options[] = { "file", "vmlinux pathname"), OPT_BOOLEAN(0, "buildid-all", &record.buildid_all, "Record build-id of all DSOs regardless of hits"), - OPT_BOOLEAN(0, "buildid-mmap", &record.buildid_mmap, - "Record build-id in map events"), + OPT_BOOLEAN_SET(0, "buildid-mmap", &record.buildid_mmap, &record.buildid_mmap_set, + "Legacy record build-id in map events option which is now the default. Behaves indentically to --no-buildid. Disable with --no-buildid-mmap"), OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename, "append timestamp to output filename"), OPT_BOOLEAN(0, "timestamp-boundary", &record.timestamp_boundary, @@ -4042,19 +4047,23 @@ int cmd_record(int argc, const char **argv) record.opts.record_switch_events = true; } + if (!rec->buildid_mmap) { + pr_debug("Disabling build id in synthesized mmap2 events.\n"); + symbol_conf.no_buildid_mmap2 = true; + } else if (rec->buildid_mmap_set) { + /* + * Explicitly passing --buildid-mmap disables buildid processing + * and cache generation. + */ + rec->no_buildid = true; + } + if (rec->buildid_mmap && !perf_can_record_build_id()) { + pr_warning("Missing support for build id in kernel mmap events. Disable this warning with --no-buildid-mmap\n"); + rec->buildid_mmap = false; + } if (rec->buildid_mmap) { - if (!perf_can_record_build_id()) { - pr_err("Failed: no support to record build id in mmap events, update your kernel.\n"); - err = -EINVAL; - goto out_opts; - } - pr_debug("Enabling build id in mmap2 events.\n"); - /* Enable mmap build id synthesizing. */ - symbol_conf.buildid_mmap2 = true; /* Enable perf_event_attr::build_id bit. */ rec->opts.build_id = true; - /* Disable build id cache. */ - rec->no_buildid = true; } if (rec->opts.record_cgroup && !perf_can_record_cgroup()) { diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h index cd9aa82c7d5a..7a80d2c14d9b 100644 --- a/tools/perf/util/symbol_conf.h +++ b/tools/perf/util/symbol_conf.h @@ -43,7 +43,7 @@ struct symbol_conf { report_individual_block, inline_name, disable_add2line_warn, - buildid_mmap2, + no_buildid_mmap2, guest_code, lazy_load_kernel_maps, keep_exited_threads, diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index 8fb2ea544d3a..f48109c14235 100644 --- a/tools/perf/util/synthetic-events.c +++ b/tools/perf/util/synthetic-events.c @@ -532,7 +532,7 @@ int perf_event__synthesize_mmap_events(const struct perf_tool *tool, event->mmap2.pid = tgid; event->mmap2.tid = pid; - if (symbol_conf.buildid_mmap2) + if (!symbol_conf.no_buildid_mmap2) perf_record_mmap2__read_build_id(&event->mmap2, machine, false); if (perf_tool__process_synth_event(tool, event, machine, process) != 0) { @@ -690,7 +690,7 @@ static int perf_event__synthesize_modules_maps_cb(struct map *map, void *data) return 0; dso = map__dso(map); - if (symbol_conf.buildid_mmap2) { + if (!symbol_conf.no_buildid_mmap2) { size = PERF_ALIGN(dso__long_name_len(dso) + 1, sizeof(u64)); event->mmap2.header.type = PERF_RECORD_MMAP2; event->mmap2.header.size = (sizeof(event->mmap2) - @@ -734,9 +734,9 @@ int perf_event__synthesize_modules(const struct perf_tool *tool, perf_event__han .process = process, .machine = machine, }; - size_t size = symbol_conf.buildid_mmap2 - ? sizeof(args.event->mmap2) - : sizeof(args.event->mmap); + size_t size = symbol_conf.no_buildid_mmap2 + ? sizeof(args.event->mmap) + : sizeof(args.event->mmap2); args.event = zalloc(size + machine->id_hdr_size); if (args.event == NULL) { @@ -1124,8 +1124,8 @@ static int __perf_event__synthesize_kernel_mmap(const struct perf_tool *tool, struct machine *machine) { union perf_event *event; - size_t size = symbol_conf.buildid_mmap2 ? - sizeof(event->mmap2) : sizeof(event->mmap); + size_t size = symbol_conf.no_buildid_mmap2 ? + sizeof(event->mmap) : sizeof(event->mmap2); struct map *map = machine__kernel_map(machine); struct kmap *kmap; int err; @@ -1159,7 +1159,7 @@ static int __perf_event__synthesize_kernel_mmap(const struct perf_tool *tool, event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL; } - if (symbol_conf.buildid_mmap2) { + if (!symbol_conf.no_buildid_mmap2) { size = snprintf(event->mmap2.filename, sizeof(event->mmap2.filename), "%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) + 1; size = PERF_ALIGN(size, sizeof(u64)); -- 2.49.0.850.g28803427d3-goog