From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 799D9C432C0 for ; Sat, 23 Nov 2019 08:16:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 558222071C for ; Sat, 23 Nov 2019 08:16:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727406AbfKWIQe (ORCPT ); Sat, 23 Nov 2019 03:16:34 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:36262 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726735AbfKWIPM (ORCPT ); Sat, 23 Nov 2019 03:15:12 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iYQZP-0002ac-6K; Sat, 23 Nov 2019 09:15:07 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 16A101C1AD6; Sat, 23 Nov 2019 09:15:02 +0100 (CET) Date: Sat, 23 Nov 2019 08:15:02 -0000 From: "tip-bot2 for Adrian Hunter" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/core] perf record: Add a function to test for kernel support for AUX area sampling Cc: Adrian Hunter , Jiri Olsa , Arnaldo Carvalho de Melo , x86 , LKML In-Reply-To: <20191115124225.5247-4-adrian.hunter@intel.com> References: <20191115124225.5247-4-adrian.hunter@intel.com> MIME-Version: 1.0 Message-ID: <157449690202.21853.14789264761246818665.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the perf/core branch of tip: Commit-ID: 9bca1a4ef5034f0a82861ac0375eb0272c5ce04e Gitweb: https://git.kernel.org/tip/9bca1a4ef5034f0a82861ac0375eb0272c5ce04e Author: Adrian Hunter AuthorDate: Fri, 15 Nov 2019 14:42:13 +02:00 Committer: Arnaldo Carvalho de Melo CommitterDate: Fri, 22 Nov 2019 10:43:24 -03:00 perf record: Add a function to test for kernel support for AUX area sampling Architectures are expected to know if AUX area sampling is supported by the hardware. Add a function perf_can_aux_sample() which will determine whether the kernel supports it. Committer notes: I reported that this message was taking place on a kernel without the required bits: # perf record --aux-sample -e '{intel_pt//u,branch-misses:u}' Error: The sys_perf_event_open() syscall returned with 7 (Argument list too long) for event (branch-misses:u). /bin/dmesg | grep -i perf may provide additional information. Adrian sent a patch addressing it, with this explanation: ---- perf_can_aux_sample_size() always returned true because it did not pass the attribute size to sys_perf_event_open, nor correctly check the return value and errno. ---- After applying it I get, later in the series, when --aux-sample is added: # perf record --aux-sample -e '{intel_pt//u,branch-misses:u}' AUX area sampling is not supported by kernel Signed-off-by: Adrian Hunter Cc: Jiri Olsa Link: http://lore.kernel.org/lkml/20191115124225.5247-4-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evlist.h | 1 + tools/perf/util/record.c | 31 +++++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index 1305140..3655b9e 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -176,6 +176,7 @@ void perf_evlist__set_id_pos(struct evlist *evlist); bool perf_can_sample_identifier(void); bool perf_can_record_switch_events(void); bool perf_can_record_cpu_wide(void); +bool perf_can_aux_sample(void); void perf_evlist__config(struct evlist *evlist, struct record_opts *opts, struct callchain_param *callchain); int record_opts__config(struct record_opts *opts); diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c index 8579505..7def661 100644 --- a/tools/perf/util/record.c +++ b/tools/perf/util/record.c @@ -136,6 +136,37 @@ bool perf_can_record_cpu_wide(void) return true; } +/* + * Architectures are expected to know if AUX area sampling is supported by the + * hardware. Here we check for kernel support. + */ +bool perf_can_aux_sample(void) +{ + struct perf_event_attr attr = { + .size = sizeof(struct perf_event_attr), + .exclude_kernel = 1, + /* + * Non-zero value causes the kernel to calculate the effective + * attribute size up to that byte. + */ + .aux_sample_size = 1, + }; + int fd; + + fd = sys_perf_event_open(&attr, -1, 0, -1, 0); + /* + * If the kernel attribute is big enough to contain aux_sample_size + * then we assume that it is supported. We are relying on the kernel to + * validate the attribute size before anything else that could be wrong. + */ + if (fd < 0 && errno == E2BIG) + return false; + if (fd >= 0) + close(fd); + + return true; +} + void perf_evlist__config(struct evlist *evlist, struct record_opts *opts, struct callchain_param *callchain) {