Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755239Ab2EBQ1Z (ORCPT ); Wed, 2 May 2012 12:27:25 -0400 Received: from merlin.infradead.org ([205.233.59.134]:38522 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753254Ab2EBQ1Y (ORCPT ); Wed, 2 May 2012 12:27:24 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Stephane Eranian , Gleb Natapov , Ingo Molnar , Joerg Roedel , Peter Zijlstra , Robert Richter , Arnaldo Carvalho de Melo Subject: [PATCH 2/2] perf stat: Fix case where guest/host monitoring is not supported by kernel Date: Wed, 2 May 2012 13:27:04 -0300 Message-Id: <1335976024-13067-3-git-send-email-acme@infradead.org> X-Mailer: git-send-email 1.7.9.2.358.g22243 In-Reply-To: <1335976024-13067-1-git-send-email-acme@infradead.org> References: <1335976024-13067-1-git-send-email-acme@infradead.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by canuck.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3113 Lines: 93 From: Stephane Eranian By default, perf stat sets exclude_guest = 1. But when you run perf on a kernel which does not support host/guest filtering, then you get an error saying the event in unsupported. This comes from the fact that when the perf_event_attr struct passed by the user is larger than the one known to the kernel there is safety check which ensures that all unknown bits are zero. But here, exclude_guest is 1 (part of the unknown bits) and thus the perf_event_open() syscall return EINVAL. To my surprise, running perf record on the same kernel did not exhibit the problem. The reason is that perf record handles the problem by catching the error and retrying with guest/host excludes set to zero. For some reason, this was not done with perf stat. This patch fixes this problem. Signed-off-by: Stephane Eranian Cc: Gleb Natapov Cc: Ingo Molnar Cc: Joerg Roedel Cc: Peter Zijlstra Cc: Robert Richter Link: http://lkml.kernel.org/r/20120427124538.GA7230@quad Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-stat.c | 33 +++++++++++++++++++++++++++++---- 1 file changed, 29 insertions(+), 4 deletions(-) diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index c941bb6..4532a78 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -283,6 +283,8 @@ static int create_perf_stat_counter(struct perf_evsel *evsel, { struct perf_event_attr *attr = &evsel->attr; struct xyarray *group_fd = NULL; + bool exclude_guest_missing = false; + int ret; if (group && evsel != first) group_fd = first->fd; @@ -293,16 +295,39 @@ static int create_perf_stat_counter(struct perf_evsel *evsel, attr->inherit = !no_inherit; - if (system_wide) - return perf_evsel__open_per_cpu(evsel, evsel_list->cpus, +retry: + if (exclude_guest_missing) + evsel->attr.exclude_guest = evsel->attr.exclude_host = 0; + + if (system_wide) { + ret = perf_evsel__open_per_cpu(evsel, evsel_list->cpus, group, group_fd); + if (ret) + goto check_ret; + return 0; + } + if (!target_pid && !target_tid && (!group || evsel == first)) { attr->disabled = 1; attr->enable_on_exec = 1; } - return perf_evsel__open_per_thread(evsel, evsel_list->threads, - group, group_fd); + ret = perf_evsel__open_per_thread(evsel, evsel_list->threads, + group, group_fd); + if (!ret) + return 0; + /* fall through */ +check_ret: + if (ret && errno == EINVAL) { + if (!exclude_guest_missing && + (evsel->attr.exclude_guest || evsel->attr.exclude_host)) { + pr_debug("Old kernel, cannot exclude " + "guest or host samples.\n"); + exclude_guest_missing = true; + goto retry; + } + } + return ret; } /* -- 1.7.9.2.358.g22243 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/