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, 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 3D990C10F27 for ; Mon, 9 Mar 2020 17:47:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23A0D21655 for ; Mon, 9 Mar 2020 17:47:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727393AbgCIRrn (ORCPT ); Mon, 9 Mar 2020 13:47:43 -0400 Received: from mga14.intel.com ([192.55.52.115]:12899 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726510AbgCIRrl (ORCPT ); Mon, 9 Mar 2020 13:47:41 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Mar 2020 10:47:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,518,1574150400"; d="scan'208";a="260490362" Received: from labuser-ice-lake-client-platform.jf.intel.com ([10.54.55.45]) by orsmga002.jf.intel.com with ESMTP; 09 Mar 2020 10:47:40 -0700 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 V2 8/9] perf c2c: Add option to enable the LBR stitching approach Date: Mon, 9 Mar 2020 10:46:38 -0700 Message-Id: <20200309174639.4594-9-kan.liang@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200309174639.4594-1-kan.liang@linux.intel.com> References: <20200309174639.4594-1-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-c2c.txt | 11 +++++++++++ tools/perf/builtin-c2c.c | 6 ++++++ 2 files changed, 17 insertions(+) diff --git a/tools/perf/Documentation/perf-c2c.txt b/tools/perf/Documentation/perf-c2c.txt index e6150f21267d..2133eb320cb0 100644 --- a/tools/perf/Documentation/perf-c2c.txt +++ b/tools/perf/Documentation/perf-c2c.txt @@ -111,6 +111,17 @@ REPORT OPTIONS --display:: Switch to HITM type (rmt, lcl) to display and sort on. Total HITMs as default. +--stitch-lbr:: + Show callgraph with stitched LBRs, which may have more complete + callgraph. The perf.data file must have been obtained using + perf c2c 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. + C2C RECORD ---------- The perf c2c record command setup options related to HITM cacheline analysis diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c index 246ac0b4d54f..c798763f62db 100644 --- a/tools/perf/builtin-c2c.c +++ b/tools/perf/builtin-c2c.c @@ -95,6 +95,7 @@ struct perf_c2c { bool use_stdio; bool stats_only; bool symbol_full; + bool stitch_lbr; /* HITM shared clines stats */ struct c2c_stats hitm_stats; @@ -273,6 +274,9 @@ static int process_sample_event(struct perf_tool *tool __maybe_unused, return -1; } + if (c2c.stitch_lbr) + al.thread->lbr_stitch_enable = true; + ret = sample__resolve_callchain(sample, &callchain_cursor, NULL, evsel, &al, sysctl_perf_event_max_stack); if (ret) @@ -2752,6 +2756,8 @@ static int perf_c2c__report(int argc, const char **argv) OPT_STRING('c', "coalesce", &coalesce, "coalesce fields", "coalesce fields: pid,tid,iaddr,dso"), OPT_BOOLEAN('f', "force", &symbol_conf.force, "don't complain, do it"), + OPT_BOOLEAN(0, "stitch-lbr", &c2c.stitch_lbr, + "Enable LBR callgraph stitching approach"), OPT_PARENT(c2c_options), OPT_END() }; -- 2.17.1