From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757173AbZELGRA (ORCPT ); Tue, 12 May 2009 02:17:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754351AbZELGQv (ORCPT ); Tue, 12 May 2009 02:16:51 -0400 Received: from bilbo.ozlabs.org ([203.10.76.25]:46756 "EHLO bilbo.ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754117AbZELGQu (ORCPT ); Tue, 12 May 2009 02:16:50 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18953.5194.205862.75538@drongo.ozlabs.ibm.com> Date: Tue, 12 May 2009 16:16:42 +1000 From: Paul Mackerras To: Corey Ashford Cc: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, Thomas Gleixner Subject: Re: [PATCH 3/5] perf_counter: rework ioctl()s In-Reply-To: <4A08A8C6.1090302@linux.vnet.ibm.com> References: <20090508165219.469818319@chello.nl> <20090508170028.837558214@chello.nl> <18951.32643.749495.538351@drongo.ozlabs.ibm.com> <4A086A89.6030905@linux.vnet.ibm.com> <18952.36878.942836.803265@cargo.ozlabs.ibm.com> <4A08A8C6.1090302@linux.vnet.ibm.com> X-Mailer: VM 8.0.12 under 22.3.1 (powerpc-unknown-linux-gnu) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Corey Ashford writes: > I was seeing that on Power5. On 5/6/2009, I sent along a test case that was > supposed to duplicate the sequence of operations, without using PAPI, to Peter > Zijlstra, cc'ing you. However, I was unable to get any signals delivered to > user space with that code, so I was unable to reproduce the problem outside of > the PAPI test case. I don't know why signal delivery doesn't work with that > test case... I spent quite a lot of time verifying that it was doing the right > thing, but could never get it to work. I tried your test program out today, with the ioctl calls changed to add an extra 0 argument, like this: ioctl(fd[0], PERF_COUNTER_IOC_ENABLE, 0); and similarly for the disable call. It all seemed to be fine. There is still a little problem with enabling counters - it doesn't happen right away. I have a patch to fix that, which I'll send out, and with that patch I get: # ./test_group_disable evt[0].config = 0 evt[1].config = 4 group_leader = -1 evt[i].wakeup_events = 0 successfully opened evt[0]. fd[0] = 3 group_leader = 3 evt[i].wakeup_events = 0 successfully opened evt[1]. fd[1] = 4 successfully attached signal handler fd 3's mmap buffer is located at 0xfffab4b3000 successfully tuned up fd 3 fd 4's mmap buffer is located at 0xfffab4aa000 successfully tuned up fd 4 enable was successful CYCLES: 20904 BRANCHES: 2413 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 4 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 4 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 4 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 signal received while counters are enabled. fd = 3 disable was successful CYCLES: 180149676 BRANCHES: 30030826 CYCLES: 180149676 BRANCHES: 30030826 CYCLES data_head: 141b0 BRANCHES data_head: 35a0 # So clearly it is getting signals when the leader is enabled, one per page of events, and not when the leader is disabled. I notice you have evt[].wakeup_events set to 0, which is presumably why we don't get more signals than we do. Paul.