From nobody Mon Feb 9 07:20:38 2026 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (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 1F3BE214A68 for ; Mon, 28 Apr 2025 21:34:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745876071; cv=none; b=tf2ge6otfurnmzYJo5Y2VphCgV7ZmyTw0po/lcx1A/0VlLHUgnF6JpteKMEp+rMC7GQ0joWZaxzzb+2KI0NOCgnl4TxGmHrI5oHxK3EiLtCQFoRuZpBEXjUIGYj4arEPhyxqJDSNvzX8RJpTaOo92R/bVQxFCn4KHOzUZr/X9PU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745876071; c=relaxed/simple; bh=PScFL3QKHD83Kd+8sQnLhjHRKeKqkKT+m+cpgcoH03w=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=Nl0piOSLlEIjbu2emhgFFdlkMVVUL8J4YZCXz5ajgl/6LdhP+NNNdZrlcwtXFku/YtfUaG3iefjO5gtZXf0i5Ijkl/xA2fTI0gxvNa7M3pz04Tgx8cpy8E3XhoIaqubOzAyrg4DYVlXZZ8Az3CFc7z7xlSSFNjLvdmvFE1QAfU0= 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=ph7B7qQj; arc=none smtp.client-ip=209.85.210.202 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="ph7B7qQj" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-736c1ea954fso2692796b3a.3 for ; Mon, 28 Apr 2025 14:34:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1745876069; x=1746480869; 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=HSs+BEdvbnIfY2dq99UXmMP4Buukql0Gb5bTAHvwkAg=; b=ph7B7qQjAbfUgFsmG3luIKpNwWX2iH18m3Ed060jtsRX79wbQP2yqEG8aYXm5gqZxv aiFRInz3GNHnPleU1IQfkpAjGZsnvsrOXMBzxf7xt3PofEHJFU4hiWr7Jfa3kL5ptRHv NwdEjJxiRhgMvyM3swknIffDPcVZTiJF2N6aTqu9WimVepqW9F3xIT9ELF4HB7sEE677 1UebDnwlUfdBj2X1V39FpIf/57KBf8k3KLD0LawTHcVnME1YA7xpQlB2+5Cq1a5B5VPC 73GpDNe/Yrad7+2BNqqP2+5Aag3lR/MNFTIRk3pIEiH3Gts4fPg5ML/GR6BjEoMV5IHY qmlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745876069; x=1746480869; 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=HSs+BEdvbnIfY2dq99UXmMP4Buukql0Gb5bTAHvwkAg=; b=bWa/0aeqxsz4xEW3TOi29dN8hYTlNOsA8wwuI6gGBGVIa0f9DpUdRLL6KiwKbF+1IA E9rHLZ8kYavj5u6azOr/+CGGxbi9Wgw7oqz8aDinqUIU6zulBdumgxNjE8nhyr7OB/lY OTpGVQNXYU4XoEnYIB6/+x9OzQxpkALoFRNULkKA95h//lVp67xwur3TfHUhggUOxXVz 73YarvXnVefbGM1SZAxbzgtBcknuU69Ty0bUizlNlJy4yYM+6WGTKRwNJCJwBmNozIbU xNw1mb9ONuitpKRV9rVukFiwwKUtUcA8/Lg7Ce5nNUkTKvATfpbHAjklgg/zwnWXiGgq ysLA== X-Forwarded-Encrypted: i=1; AJvYcCV9SLZthPQZtmWUFpv6LjJVZjcpgofH3m5zI/HfzSgZ0PeMvV8SK4DRV/FGbfgCwVdVppf7Xa18s7KR39s=@vger.kernel.org X-Gm-Message-State: AOJu0Ywc3/GVSMPgl48z8Mb2nL8xyai46Bl4JPcIdooM1sAPth6TFjKl gp/vMeuh2veLY7Om+lMgkC8IuVHILFP8nald5Bn5Ri04InA5bY+6xKAFzabjCfx7BC/gvW+TPeM IipFWNA== X-Google-Smtp-Source: AGHT+IFcsBuxLiRKFxo6cxliw7p+n3n5l2JnUxq7Z0GFhsWt1MiIhCDgVcaUM/hovjHWg7X6AItekzXO1Bba X-Received: from pfoc2.prod.google.com ([2002:aa7:8802:0:b0:73c:26bd:133c]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:9282:b0:736:5753:12f7 with SMTP id d2e1a72fcca58-74028f9382amr954698b3a.3.1745876069395; Mon, 28 Apr 2025 14:34:29 -0700 (PDT) Date: Mon, 28 Apr 2025 14:34:08 -0700 In-Reply-To: <20250428213409.1417584-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250428213409.1417584-1-irogers@google.com> X-Mailer: git-send-email 2.49.0.901.g37484f566f-goog Message-ID: <20250428213409.1417584-10-irogers@google.com> Subject: [PATCH v3 9/9] 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-Transfer-Encoding: quoted-printable 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=3DfXP7jN_QrGUcd55_QH5J-Y-FCa= J6=3DNaHVtyx0oyNh8_-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 =3D lseek(data->dir.files[i].fd, 0, SEEK_CUR); } =20 + /* Buildid scanning disabled or build ID in kernel and synthesized map ev= ents. */ if (!rec->no_buildid) { process_buildids(rec); =20 @@ -2966,6 +2968,8 @@ static int perf_record_config(const char *var, const = char *value, void *cb) rec->no_buildid =3D true; else if (!strcmp(value, "mmap")) rec->buildid_mmap =3D true; + else if (!strcmp(value, "no-mmap")) + rec->buildid_mmap =3D false; else return -1; return 0; @@ -3349,6 +3353,7 @@ static struct record record =3D { .ctl_fd_ack =3D -1, .synth =3D PERF_SYNTH_ALL, }, + .buildid_mmap =3D true, }; =20 const char record_callchain_help[] =3D CALLCHAIN_RECORD_HELP @@ -3514,8 +3519,8 @@ static struct option __record_options[] =3D { "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 =3D true; } =20 + if (!rec->buildid_mmap) { + pr_debug("Disabling build id in synthesized mmap2 events.\n"); + symbol_conf.no_buildid_mmap2 =3D true; + } else if (rec->buildid_mmap_set) { + /* + * Explicitly passing --buildid-mmap disables buildid processing + * and cache generation. + */ + rec->no_buildid =3D 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 =3D false; + } if (rec->buildid_mmap) { - if (!perf_can_record_build_id()) { - pr_err("Failed: no support to record build id in mmap events, update yo= ur kernel.\n"); - err =3D -EINVAL; - goto out_opts; - } - pr_debug("Enabling build id in mmap2 events.\n"); - /* Enable mmap build id synthesizing. */ - symbol_conf.buildid_mmap2 =3D true; /* Enable perf_event_attr::build_id bit. */ rec->opts.build_id =3D true; - /* Disable build id cache. */ - rec->no_buildid =3D true; } =20 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 69b98023ce74..638d7dd7fa4b 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 per= f_tool *tool, event->mmap2.pid =3D tgid; event->mmap2.tid =3D pid; =20 - if (symbol_conf.buildid_mmap2) + if (!symbol_conf.no_buildid_mmap2) perf_record_mmap2__read_build_id(&event->mmap2, machine, false); =20 if (perf_tool__process_synth_event(tool, event, machine, process) !=3D 0= ) { @@ -690,7 +690,7 @@ static int perf_event__synthesize_modules_maps_cb(struc= t map *map, void *data) return 0; =20 dso =3D map__dso(map); - if (symbol_conf.buildid_mmap2) { + if (!symbol_conf.no_buildid_mmap2) { size =3D PERF_ALIGN(dso__long_name_len(dso) + 1, sizeof(u64)); event->mmap2.header.type =3D PERF_RECORD_MMAP2; event->mmap2.header.size =3D (sizeof(event->mmap2) - @@ -734,9 +734,9 @@ int perf_event__synthesize_modules(const struct perf_to= ol *tool, perf_event__han .process =3D process, .machine =3D machine, }; - size_t size =3D symbol_conf.buildid_mmap2 - ? sizeof(args.event->mmap2) - : sizeof(args.event->mmap); + size_t size =3D symbol_conf.no_buildid_mmap2 + ? sizeof(args.event->mmap) + : sizeof(args.event->mmap2); =20 args.event =3D zalloc(size + machine->id_hdr_size); if (args.event =3D=3D 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 =3D symbol_conf.buildid_mmap2 ? - sizeof(event->mmap2) : sizeof(event->mmap); + size_t size =3D symbol_conf.no_buildid_mmap2 ? + sizeof(event->mmap) : sizeof(event->mmap2); struct map *map =3D 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 =3D PERF_RECORD_MISC_GUEST_KERNEL; } =20 - if (symbol_conf.buildid_mmap2) { + if (!symbol_conf.no_buildid_mmap2) { size =3D snprintf(event->mmap2.filename, sizeof(event->mmap2.filename), "%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) + 1; size =3D PERF_ALIGN(size, sizeof(u64)); --=20 2.49.0.901.g37484f566f-goog