From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e37.co.us.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id AA8B92C0080 for ; Fri, 25 Jan 2013 10:25:29 +1100 (EST) Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 24 Jan 2013 16:25:26 -0700 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 3DAD51FF0038 for ; Thu, 24 Jan 2013 16:25:24 -0700 (MST) Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0ONPNnu351090 for ; Thu, 24 Jan 2013 16:25:24 -0700 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r0ONPMxU001958 for ; Thu, 24 Jan 2013 16:25:23 -0700 Date: Thu, 24 Jan 2013 15:25:23 -0800 From: Sukadev Bhattiprolu To: Benjamin Herrenschmidt Subject: [PATCH][v2] perf/Power: PERF_EVENT_IOC_ENABLE does not reenable event Message-ID: <20130124232523.GA12162@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Maynard Johnson , Anton Blanchard , Paul Mackerras , linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , perf/Power: PERF_EVENT_IOC_ENABLE does not reenable event If we disable a perf event because we exceeded the specified ->event_limit, power_pmu_stop() sets the PERF_HES_STOPPED flag on the event. If the application then re-enables the event using PERF_EVENT_IOC_ENABLE ioctl, we don't ever clear this STOPPED flag. Consequently, the user space is never notified of the event. Following message has more background and test case. http://lists.eecs.utk.edu/pipermail/ptools-perfapi/2012-October/002528.html Used the following test cases to verify that this patch works on latest PAPI. $ papi.git/src/ctests/nonthread PAPI_TOT_CYC@5000000 $ papi.git/src/ctests/overflow_single_event Changelog[v2]: - [Paul Mackerras] Also clear PERF_HES_UPTODATE flag since we are restarting the event; cleanup comments and patch description. Signed-off-by: Sukadev Bhattiprolu --- arch/powerpc/perf/core-book3s.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index aa2465e..4b1e584 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -880,8 +880,16 @@ static int power_pmu_add(struct perf_event *event, int ef_flags) cpuhw->events[n0] = event->hw.config; cpuhw->flags[n0] = event->hw.event_base; + /* + * This event may have been disabled/stopped in record_and_restart() + * because we exceeded the ->event_limit. If re-starting the event, + * clear the ->hw.state (STOPPED and UPTODATE flags), so the user + * notification is re-enabled. + */ if (!(ef_flags & PERF_EF_START)) event->hw.state = PERF_HES_STOPPED | PERF_HES_UPTODATE; + else + event->hw.state = 0; /* * If group events scheduling transaction was started, -- 1.7.1