From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754780Ab3BDMdc (ORCPT ); Mon, 4 Feb 2013 07:33:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34503 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753814Ab3BDMd3 (ORCPT ); Mon, 4 Feb 2013 07:33:29 -0500 From: Jiri Olsa To: linux-kernel@vger.kernel.org Cc: Jiri Olsa , Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Paul Mackerras , Corey Ashford , Frederic Weisbecker , Namhyung Kim Subject: [PATCH 02/11] perf: Add PERF_EVENT_IOC_ID ioctl to return event ID Date: Mon, 4 Feb 2013 13:32:56 +0100 Message-Id: <1359981185-16819-3-git-send-email-jolsa@redhat.com> In-Reply-To: <1359981185-16819-1-git-send-email-jolsa@redhat.com> References: <1359981185-16819-1-git-send-email-jolsa@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "jolsa@redhat.com" The only way to get the event ID is by reading the event fd, followed by parsing the ID value out of the returned data. While this is ok for current read format used by perf tool, it is not ok when we use PERF_FORMAT_GROUP format. With this format the data are returned for the whole group and there's no way to find out what ID belongs to our fd (if we are not group leader event). Adding a simple ioctl that returns event primary ID for given fd. Signed-off-by: Jiri Olsa Cc: Arnaldo Carvalho de Melo Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Paul Mackerras Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Namhyung Kim --- include/uapi/linux/perf_event.h | 1 + kernel/events/core.c | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 9fa9c62..b4ea8ed 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -316,6 +316,7 @@ struct perf_event_attr { #define PERF_EVENT_IOC_PERIOD _IOW('$', 4, __u64) #define PERF_EVENT_IOC_SET_OUTPUT _IO ('$', 5) #define PERF_EVENT_IOC_SET_FILTER _IOW('$', 6, char *) +#define PERF_EVENT_IOC_ID _IOR('$', 7, u64 *) enum perf_event_ioc_flags { PERF_IOC_FLAG_GROUP = 1U << 0, diff --git a/kernel/events/core.c b/kernel/events/core.c index 301079d..4081261 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3277,6 +3277,15 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case PERF_EVENT_IOC_PERIOD: return perf_event_period(event, (u64 __user *)arg); + case PERF_EVENT_IOC_ID: + { + u64 id = primary_event_id(event); + + if (copy_to_user((void __user *)arg, &id, sizeof(id))) + return -EFAULT; + return 0; + } + case PERF_EVENT_IOC_SET_OUTPUT: { int ret; -- 1.7.11.7