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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 501D3C3F2CD for ; Fri, 28 Feb 2020 16:32:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E225246BB for ; Fri, 28 Feb 2020 16:32:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726995AbgB1Qc1 (ORCPT ); Fri, 28 Feb 2020 11:32:27 -0500 Received: from mga14.intel.com ([192.55.52.115]:35576 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726933AbgB1QcZ (ORCPT ); Fri, 28 Feb 2020 11:32:25 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Feb 2020 08:32:25 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,496,1574150400"; d="scan'208";a="227593091" Received: from labuser-ice-lake-client-platform.jf.intel.com ([10.54.55.45]) by orsmga007.jf.intel.com with ESMTP; 28 Feb 2020 08:32:25 -0800 From: kan.liang@linux.intel.com To: acme@kernel.org, jolsa@redhat.com, peterz@infradead.org, mingo@redhat.com, linux-kernel@vger.kernel.org Cc: namhyung@kernel.org, adrian.hunter@intel.com, mathieu.poirier@linaro.org, ravi.bangoria@linux.ibm.com, alexey.budankov@linux.intel.com, vitaly.slobodskoy@intel.com, pavel.gerasimov@intel.com, mpe@ellerman.id.au, eranian@google.com, ak@linux.intel.com, Kan Liang Subject: [PATCH 09/12] perf script: Add option to enable the LBR stitching approach Date: Fri, 28 Feb 2020 08:30:08 -0800 Message-Id: <20200228163011.19358-10-kan.liang@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200228163011.19358-1-kan.liang@linux.intel.com> References: <20200228163011.19358-1-kan.liang@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kan Liang 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. Reviewed-by: Andi Kleen Signed-off-by: Kan Liang --- tools/perf/Documentation/perf-script.txt | 11 +++++++++++ tools/perf/builtin-script.c | 6 ++++++ 2 files changed, 17 insertions(+) diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt index 2599b057e47b..472f20f1e479 100644 --- a/tools/perf/Documentation/perf-script.txt +++ b/tools/perf/Documentation/perf-script.txt @@ -426,6 +426,17 @@ include::itrace.txt[] --show-on-off-events:: Show the --switch-on/off events too. +--stitch-lbr:: + Show callgraph with stitched LBRs, which may have more complete + callgraph. The perf.data file must have been obtained using + perf record --call-graph lbr. + 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. + SEE ALSO -------- linkperf:perf-record[1], linkperf:perf-script-perl[1], diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index acf3107bbda2..c229e0199003 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -1687,6 +1687,7 @@ struct perf_script { bool show_bpf_events; bool allocated; bool per_event_dump; + bool stitch_lbr; struct evswitch evswitch; struct perf_cpu_map *cpus; struct perf_thread_map *threads; @@ -1913,6 +1914,9 @@ static void process_event(struct perf_script *script, if (PRINT_FIELD(IP)) { struct callchain_cursor *cursor = NULL; + if (script->stitch_lbr) + al->thread->lbr_stitch_enable = true; + if (symbol_conf.use_callchain && sample->callchain && thread__resolve_callchain(al->thread, &callchain_cursor, evsel, sample, NULL, NULL, scripting_max_stack) == 0) @@ -3602,6 +3606,8 @@ int cmd_script(int argc, const char **argv) "file", "file saving guest os /proc/kallsyms"), OPT_STRING(0, "guestmodules", &symbol_conf.default_guest_modules, "file", "file saving guest os /proc/modules"), + OPT_BOOLEAN('\0', "stitch-lbr", &script.stitch_lbr, + "Enable LBR callgraph stitching approach"), OPTS_EVSWITCH(&script.evswitch), OPT_END() }; -- 2.17.1