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 AD0BFC55185 for ; Wed, 22 Apr 2020 12:22:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A1A422206 for ; Wed, 22 Apr 2020 12:22:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728589AbgDVMWm (ORCPT ); Wed, 22 Apr 2020 08:22:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1728482AbgDVMRc (ORCPT ); Wed, 22 Apr 2020 08:17:32 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A1DC8C03C1AD; Wed, 22 Apr 2020 05:17:30 -0700 (PDT) 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 1jREJT-0007YQ-Cn; Wed, 22 Apr 2020 14:17:11 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id E6EF41C02FC; Wed, 22 Apr 2020 14:17:10 +0200 (CEST) Date: Wed, 22 Apr 2020 12:17:10 -0000 From: "tip-bot2 for Kan Liang" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/core] perf top: Add option to enable the LBR stitching approach Cc: Kan Liang , Andi Kleen , Jiri Olsa , Arnaldo Carvalho de Melo , Adrian Hunter , Alexey Budankov , Mathieu Poirier , Michael Ellerman , Namhyung Kim , Pavel Gerasimov , Peter Zijlstra , Ravi Bangoria , Stephane Eranian , Vitaly Slobodskoy , x86 , LKML In-Reply-To: <20200319202517.23423-16-kan.liang@linux.intel.com> References: <20200319202517.23423-16-kan.liang@linux.intel.com> MIME-Version: 1.0 Message-ID: <158755783050.28353.14034885809740386409.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: 13e0c844fa097f657bd8204fd574477c34f47a0c Gitweb: https://git.kernel.org/tip/13e0c844fa097f657bd8204fd574477c34f47a0c Author: Kan Liang AuthorDate: Thu, 19 Mar 2020 13:25:15 -07:00 Committer: Arnaldo Carvalho de Melo CommitterDate: Sat, 18 Apr 2020 09:05:01 -03:00 perf top: Add option to enable the LBR stitching approach With the LBR stitching approach, the reconstructed LBR call stack can break the HW limitation. However, it may reconstruct invalid call stacks in some cases, e.g. exception handing such as setjmp/longjmp. Also, it may impact the processing time especially when the number of samples with stitched LBRs are huge. Add an option to enable the approach. The option must be used with --call-graph lbr. Signed-off-by: Kan Liang Reviewed-by: Andi Kleen Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexey Budankov Cc: Mathieu Poirier Cc: Michael Ellerman Cc: Namhyung Kim Cc: Pavel Gerasimov Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Stephane Eranian Cc: Vitaly Slobodskoy Link: http://lore.kernel.org/lkml/20200319202517.23423-16-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-top.txt | 9 +++++++++ tools/perf/builtin-top.c | 11 +++++++++++ tools/perf/util/top.h | 1 + 3 files changed, 21 insertions(+) diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt index 487737a..20227da 100644 --- a/tools/perf/Documentation/perf-top.txt +++ b/tools/perf/Documentation/perf-top.txt @@ -319,6 +319,15 @@ Default is to monitor all CPUS. go straight to the histogram browser, just like 'perf top' with no events explicitely specified does. +--stitch-lbr:: + Show callgraph with stitched LBRs, which may have more complete + callgraph. The option must be used with --call-graph lbr recording. + Disabled by default. In common cases with call stack overflows, + it can recreate better call stacks than the default lbr call stack + output. But this approach is not full proof. There can be cases + where it creates incorrect call stacks from incorrect matches. + The known limitations include exception handing such as + setjmp/longjmp will have calls/returns not match. INTERACTIVE PROMPTING KEYS -------------------------- diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 289cf83..6b067a5 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -33,6 +33,7 @@ #include "util/map.h" #include "util/mmap.h" #include "util/session.h" +#include "util/thread.h" #include "util/symbol.h" #include "util/synthetic-events.h" #include "util/top.h" @@ -775,6 +776,9 @@ static void perf_event__process_sample(struct perf_tool *tool, if (machine__resolve(machine, &al, sample) < 0) return; + if (top->stitch_lbr) + al.thread->lbr_stitch_enable = true; + if (!machine->kptr_restrict_warned && symbol_conf.kptr_restrict && al.cpumode == PERF_RECORD_MISC_KERNEL) { @@ -1571,6 +1575,8 @@ int cmd_top(int argc, const char **argv) "Sort the output by the event at the index n in group. " "If n is invalid, sort by the first event. " "WARNING: should be used on grouped events."), + OPT_BOOLEAN(0, "stitch-lbr", &top.stitch_lbr, + "Enable LBR callgraph stitching approach"), OPTS_EVSWITCH(&top.evswitch), OPT_END() }; @@ -1640,6 +1646,11 @@ int cmd_top(int argc, const char **argv) } } + if (top.stitch_lbr && !(callchain_param.record_mode == CALLCHAIN_LBR)) { + pr_err("Error: --stitch-lbr must be used with --call-graph lbr\n"); + goto out_delete_evlist; + } + if (opts->branch_stack && callchain_param.enabled) symbol_conf.show_branchflag_count = true; diff --git a/tools/perf/util/top.h b/tools/perf/util/top.h index f117d4f..45dc84d 100644 --- a/tools/perf/util/top.h +++ b/tools/perf/util/top.h @@ -36,6 +36,7 @@ struct perf_top { bool use_tui, use_stdio; bool vmlinux_warned; bool dump_symtab; + bool stitch_lbr; struct hist_entry *sym_filter_entry; struct evsel *sym_evsel; struct perf_session *session;