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 182B0C3F2D2 for ; Fri, 28 Feb 2020 16:32:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE665246B9 for ; Fri, 28 Feb 2020 16:32:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727072AbgB1Qcj (ORCPT ); Fri, 28 Feb 2020 11:32:39 -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 S1726961AbgB1Qc0 (ORCPT ); Fri, 28 Feb 2020 11:32:26 -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 08:32:26 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,496,1574150400"; d="scan'208";a="227593098" Received: from labuser-ice-lake-client-platform.jf.intel.com ([10.54.55.45]) by orsmga007.jf.intel.com with ESMTP; 28 Feb 2020 08:32:26 -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 10/12] perf top: Add option to enable the LBR stitching approach Date: Fri, 28 Feb 2020 08:30:09 -0800 Message-Id: <20200228163011.19358-11-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. The option must be used with --call-graph lbr. Reviewed-by: Andi Kleen Signed-off-by: Kan Liang --- 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 324b6b53c86b..0648d96981fe 100644 --- a/tools/perf/Documentation/perf-top.txt +++ b/tools/perf/Documentation/perf-top.txt @@ -310,6 +310,15 @@ 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 8affcab75604..fd63e066f235 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" @@ -766,6 +767,9 @@ 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) { @@ -1543,6 +1547,8 @@ int cmd_top(int argc, const char **argv) "number of thread to run event synthesize"), OPT_BOOLEAN(0, "namespaces", &opts->record_namespaces, "Record namespaces events"), + OPT_BOOLEAN(0, "stitch-lbr", &top.stitch_lbr, + "Enable LBR callgraph stitching approach"), OPTS_EVSWITCH(&top.evswitch), OPT_END() }; @@ -1612,6 +1618,11 @@ 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 f117d4f4821e..45dc84ddff37 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; -- 2.17.1