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 CDCE4CA9EB0 for ; Mon, 21 Oct 2019 20:04:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ADDB22084C for ; Mon, 21 Oct 2019 20:04:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730325AbfJUUEf (ORCPT ); Mon, 21 Oct 2019 16:04:35 -0400 Received: from mga12.intel.com ([192.55.52.136]:57214 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730293AbfJUUE3 (ORCPT ); Mon, 21 Oct 2019 16:04:29 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Oct 2019 13:04:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,324,1566889200"; d="scan'208";a="201467428" Received: from labuser-ice-lake-client-platform.jf.intel.com ([10.54.55.125]) by orsmga006.jf.intel.com with ESMTP; 21 Oct 2019 13:04:28 -0700 From: kan.liang@linux.intel.com To: peterz@infradead.org, acme@kernel.org, mingo@kernel.org, linux-kernel@vger.kernel.org Cc: jolsa@kernel.org, namhyung@kernel.org, vitaly.slobodskoy@intel.com, pavel.gerasimov@intel.com, ak@linux.intel.com, eranian@google.com, Kan Liang Subject: [PATCH V2 12/13] perf c2c: Add option to enable the LBR stitching approach Date: Mon, 21 Oct 2019 13:03:13 -0700 Message-Id: <20191021200314.1613-13-kan.liang@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191021200314.1613-1-kan.liang@linux.intel.com> References: <20191021200314.1613-1-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 3542b6ab9813..c3658986c38a 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) @@ -2746,6 +2750,8 @@ 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