From nobody Wed Oct 8 18:16:18 2025 Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) (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 F16F12F3C06; Wed, 25 Jun 2025 23:16:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750893365; cv=none; b=rcfKoLcgrwE3wSVu4lrpM+EaG54lDBClzcTFR3r3rIH4QcKc3XdC4CFjfM1YB6dkFgssg0ArhuU95HOuWqskEwEU96Jf32NEf2amTHjtTzpgtR3NqE07XlYX8Px9ZoMtIQVeqBjjMwg8ZP7dfp5lKnjco9sazC67vnG0rWhe07k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750893365; c=relaxed/simple; bh=uOx5DfUnBLxP9fI1uU9zO1GwRE8LdxHgs3BL/mHcvYk=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=ssQ74/ouAGWmpaQxwhPqKkQpSy1h2PKWTwpqU/VPupi0eZNOIgDEXsEhXU3yU0ivUyf+GGEtGB3P939yk93biiKfwqa+l2wz58WekM/Uy4lS6l6KodPnlw/RNUyJ7/ADheMgEZbIJnegHSM3ZwNlvUKbRv9FI+ZAHYvKpKFIKb4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 6DE801407C1; Wed, 25 Jun 2025 23:16:01 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: nevets@goodmis.org) by omf03.hostedemail.com (Postfix) with ESMTPA id 29DF86000F; Wed, 25 Jun 2025 23:15:58 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1uUZLr-000000044ji-1LZ0; Wed, 25 Jun 2025 19:16:23 -0400 Message-ID: <20250625231623.181524553@goodmis.org> User-Agent: quilt/0.68 Date: Wed, 25 Jun 2025 19:15:50 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Jens Axboe Subject: [PATCH v11 09/11] perf record: Enable defer_callchain for user callchains References: <20250625231541.584226205@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Rspamd-Server: rspamout02 X-Rspamd-Queue-Id: 29DF86000F X-Stat-Signature: 4mk4s9infhjyx3447tsg687s1cxrscxj X-Session-Marker: 6E657665747340676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX18xXZaT/jfb217i4lEktUc0qNEfZqCYGtc= X-HE-Tag: 1750893358-116092 X-HE-Meta: U2FsdGVkX18eVzlLpfctSdzhsJC5l0rTb2uPMErOIBQO3q40i/YA90x/KozHdzxVdgLgdQ6wq6n4tizCQD2oOPSJajdiB2LboK2Xqa++vs8YwEWhPCUJBLgHhSPQvoYE8MLwlwCbU0AtYLg8T2b1qu4z180tTUDfjv4hAyH+godDBgKbz1LPNxkGBIrfnRbfkngpVDlU9qLO78Rkrp4OyQj8S9oyJy28fIFDj2j7Wsk5wAcaVBPpo+DNlTf54j/rR+Ck1iQpHxBq10MHxe4mwZvNR9YSp6/O7xkaVD1rY7pRO1fYThI1s4MpqAhZBN/9GnB+maNSPFE72VEHCHnRsnA6nF0iofEcoJ+8mp2LYH/iWjn5KeKdHSOwwK3EEInroXYH3ARFB7Wp5fOsFr/G7VyxLPxaihs3z+jkuxGybkY= Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Namhyung Kim And add the missing feature detection logic to clear the flag on old kernels. $ perf record -g -vv true ... ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|CALLCHAIN|PERIOD read_format ID|LOST disabled 1 inherit 1 mmap 1 comm 1 freq 1 enable_on_exec 1 task 1 sample_id_all 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 defer_callchain 1 ------------------------------------------------------------ sys_perf_event_open: pid 162755 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -22 switching off deferred callchain support Signed-off-by: Namhyung Kim Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- tools/perf/util/evsel.c | 24 ++++++++++++++++++++++++ tools/perf/util/evsel.h | 1 + 2 files changed, 25 insertions(+) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 6176c31b57ea..c942983b870e 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1076,6 +1076,14 @@ static void __evsel__config_callchain(struct evsel *= evsel, struct record_opts *o } } =20 + if (param->record_mode =3D=3D CALLCHAIN_FP && !attr->exclude_callchain_us= er) { + /* + * Enable deferred callchains optimistically. It'll be switched + * off later if the kernel doesn't support it. + */ + attr->defer_callchain =3D 1; + } + if (function) { pr_info("Disabling user space callchains for function trace event.\n"); attr->exclude_callchain_user =3D 1; @@ -2124,6 +2132,8 @@ static int __evsel__prepare_open(struct evsel *evsel,= struct perf_cpu_map *cpus, =20 static void evsel__disable_missing_features(struct evsel *evsel) { + if (perf_missing_features.defer_callchain) + evsel->core.attr.defer_callchain =3D 0; if (perf_missing_features.inherit_sample_read && evsel->core.attr.inherit= && (evsel->core.attr.sample_type & PERF_SAMPLE_READ)) evsel->core.attr.inherit =3D 0; @@ -2398,6 +2408,15 @@ static bool evsel__detect_missing_features(struct ev= sel *evsel, struct perf_cpu =20 /* Please add new feature detection here. */ =20 + attr.defer_callchain =3D true; + attr.sample_type =3D PERF_SAMPLE_CALLCHAIN; + if (has_attr_feature(&attr, /*flags=3D*/0)) + goto found; + perf_missing_features.defer_callchain =3D true; + pr_debug2("switching off deferred callchain support\n"); + attr.defer_callchain =3D false; + attr.sample_type =3D 0; + attr.inherit =3D true; attr.sample_type =3D PERF_SAMPLE_READ; if (has_attr_feature(&attr, /*flags=3D*/0)) @@ -2509,6 +2528,11 @@ static bool evsel__detect_missing_features(struct ev= sel *evsel, struct perf_cpu errno =3D old_errno; =20 check: + if (evsel->core.attr.defer_callchain && + evsel->core.attr.sample_type & PERF_SAMPLE_CALLCHAIN && + perf_missing_features.defer_callchain) + return true; + if (evsel->core.attr.inherit && (evsel->core.attr.sample_type & PERF_SAMPLE_READ) && perf_missing_features.inherit_sample_read) diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index 6dbc9690e0c9..a01c1de8f95f 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -221,6 +221,7 @@ struct perf_missing_features { bool branch_counters; bool aux_action; bool inherit_sample_read; + bool defer_callchain; }; =20 extern struct perf_missing_features perf_missing_features; --=20 2.47.2