From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756493AbaHVNHe (ORCPT ); Fri, 22 Aug 2014 09:07:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37212 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756243AbaHVNFz (ORCPT ); Fri, 22 Aug 2014 09:05:55 -0400 From: Jiri Olsa To: linux-kernel@vger.kernel.org Cc: Jiri Olsa , Andi Kleen , Arnaldo Carvalho de Melo , Corey Ashford , David Ahern , Frederic Weisbecker , Ingo Molnar , "Jen-Cheng(Tommy) Huang" , Namhyung Kim , Paul Mackerras , Peter Zijlstra , Stephane Eranian Subject: [PATCH 2/5] perf: Allow PERF_FORMAT_GROUP format on inherited events Date: Fri, 22 Aug 2014 15:05:15 +0200 Message-Id: <1408712718-19656-3-git-send-email-jolsa@kernel.org> In-Reply-To: <1408712718-19656-1-git-send-email-jolsa@kernel.org> References: <1408712718-19656-1-git-send-email-jolsa@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I assume the reason for this being disabled is the difficulty to read child events once in perf overflow routine, thus the perf_output_read_group function. The read syscall function perf_event_read_group seems to handle this nicely. My goal is to be able to read all events in group on leader sample by using the PERF_SAMPLE_READ with PERF_FORMAT_GROUP format. Once the monitored process forks, I need the child processes/events do the same and store samples into parents ring buffer. So I need all events sample just to report their own value (without child events being included). Thus switching the perf_event_count call for simple read of event->count. Reported-by: Jen-Cheng(Tommy) Huang Cc: Andi Kleen Cc: Arnaldo Carvalho de Melo Cc: Corey Ashford Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jen-Cheng(Tommy) Huang Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Signed-off-by: Jiri Olsa --- kernel/events/core.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index a1d220cf739b..315502bf733b 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4611,9 +4611,6 @@ static void perf_output_read_one(struct perf_output_handle *handle, __output_copy(handle, values, n * sizeof(u64)); } -/* - * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. - */ static void perf_output_read_group(struct perf_output_handle *handle, struct perf_event *event, u64 enabled, u64 running) @@ -4634,7 +4631,7 @@ static void perf_output_read_group(struct perf_output_handle *handle, if (leader != event) leader->pmu->read(leader); - values[n++] = perf_event_count(leader); + values[n++] = local64_read(&leader->count); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); @@ -4647,7 +4644,7 @@ static void perf_output_read_group(struct perf_output_handle *handle, (sub->state == PERF_EVENT_STATE_ACTIVE)) sub->pmu->read(sub); - values[n++] = perf_event_count(sub); + values[n++] = local64_read(&sub->count); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(sub); @@ -6956,12 +6953,6 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, local64_set(&hwc->period_left, hwc->sample_period); - /* - * we currently do not support PERF_FORMAT_GROUP on inherited events - */ - if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) - goto err_ns; - pmu = perf_init_event(event); if (!pmu) goto err_ns; -- 1.8.3.1