From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751382AbdKHH51 (ORCPT ); Wed, 8 Nov 2017 02:57:27 -0500 Received: from mail-pg0-f68.google.com ([74.125.83.68]:52816 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751143AbdKHH4w (ORCPT ); Wed, 8 Nov 2017 02:56:52 -0500 X-Google-Smtp-Source: ABhQp+TpjjPFf3tejj2CNZSG9vcIorwyMHaZ9aM7Xhnmrq09rHyWZ7XpGDcvLadANZETtaFpQ17CsQ== From: Stephane Eranian To: linux-kernel@vger.kernel.org Cc: acme@redhat.com, peterz@infradead.org, mingo@elte.hu, ak@linux.intel.com, kan.liang@intel.com, jolsa@redhat.com Subject: [PATCH v3 4/5] perf/record: add documentation for sampling skid ip Date: Tue, 7 Nov 2017 23:56:36 -0800 Message-Id: <1510127797-22483-5-git-send-email-eranian@google.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1510127797-22483-1-git-send-email-eranian@google.com> References: <1510127797-22483-1-git-send-email-eranian@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds documentation to describe how to use the skid ip support with perf record. The sample type can be provided per event as follows: pmu_instance/...,skid-ip=1/ For instance on Intel X86: $ perf record -e cpu/event=0xc5,skid-ip=1/pp does record the precise address of retired branches and their target. Signed-off-by: Stephane Eranian --- tools/perf/Documentation/perf-record.txt | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 5a626ef666c2..3b156fa03c99 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -57,6 +57,14 @@ OPTIONS FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and "no" for disable callgraph. - 'stack-size': user stack size for dwarf mode + - 'skid_ip' : boolean, captures the unmodified interrupt instruction pointer + (IP) in each sample. Usually with event-based sampling, the IP + has skid and rarely point to the instruction which caused the + event to overflow. On some architectures, the hardware can eliminate + the skid and perf_events returns it as the IP with precise sampling is + enabled. But for certain measurements, it may be useful to have both + the correct and skid ip. This option enable capturing the skid ip in + additional to the corrected ip. Default is: false See the linkperf:perf-list[1] man page for more parameters. -- 2.7.4