From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759098Ab0LNCK3 (ORCPT ); Mon, 13 Dec 2010 21:10:29 -0500 Received: from mga11.intel.com ([192.55.52.93]:37547 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759086Ab0LNCK1 (ORCPT ); Mon, 13 Dec 2010 21:10:27 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.59,339,1288594800"; d="scan'208";a="636049917" Subject: Re: [RFC PATCH 3/3 v3] perf: Update perf tool to monitor uncore events From: Lin Ming To: Corey Ashford Cc: Peter Zijlstra , Stephane Eranian , Andi Kleen , Ingo Molnar , Frederic Weisbecker , Arjan van de Ven , lkml , Carl Love In-Reply-To: <4D06C846.4030804@linux.vnet.ibm.com> References: <1291267238.2405.315.camel@minggr.sh.intel.com> <4D06C846.4030804@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 14 Dec 2010 10:15:08 +0800 Message-ID: <1292292908.10384.137.camel@minggr.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2010-12-14 at 09:28 +0800, Corey Ashford wrote: > On 12/01/2010 09:20 PM, Lin Ming wrote: > > Uncore events are monitored with raw events with "ru" prefix("u" for uncore). > > Note that, per-task uncore event is not allowed. > > > > $ ./perf stat -e ru0101 -- ls > > No permission to collect stats. > > Consider tweaking /proc/sys/kernel/perf_event_paranoid. > > > > ./perf stat -a -C 0 -e ru0101 -- ls > > Sorry for replying to this thread so late, but I have some concerns > about this modification. > > First of all, "uncore" is an x86-specific term and so it's not clear to > me if you meant for all arches to utilize this encoding for all "not > core but on the same die" events (IBM Power arch refers to this as > "nest" logic). > > In the case of the IBM PowerEN chip (aka WireSpeed Processor) we have a > large number of "uncore" PMUs. It's not clear to me how we should break > them up using the syntax you've suggested here. Until now, we (IBM) > have stuck with encoding all PowerEN nest events as PERF_TYPE_RAW and > utilizing the 64-bit config value to encode which PMU, which event, and > other necessary event attribute bits. > > In one scenario, we could utilize the "u" encoding as suggested in this > patch, but then we'd be stuck with encoding the specific PMU into the > config value, really not buying us any convenience. > > Another way might be to introduce a bunch of new prefixes for each of > the PMU's and add corresponding PERF_TYPE_* values. Do we want a bunch > of arch-specific PERF_TYPE_* values in include/linux/perf_event.h? > Having that many PMUs, we might want a more sophisticated prefix scheme, > perhaps something like what Stephane Eranian uses in libpfm4: > ::nnnn, e.g: > > perf stat -C 0 -e runc::0101 > or more verbosely, > perf stat -C 0 -e runcore::0101 > > For the PowerEN chip, we have PMUs for these nest functional units: > XML accelerator > Regular expression accelerator > Crypto accelerator > PowerBus interface chiplet (0..3) > Network accelerator > Memory controller Synchronous (0..1) > Memory controller Asynchronous (0..1) > etc. > > I can see value in adding something like: > > perf stat -C 0 -e rmcs0::1d > > On the other hand, I don't want to get carried away with this, when we > have the sysfs solution coming down the road, which I think will reduce > or eliminate the need for these prefixes. > > Is PERF_TYPE_UNCORE and the "u" encoding intended to be a temporary > solution? How do you envision someone using sysfs to specify an uncore > event (especially one with a raw encoding)? Yes, they are temporary solution. I use it to easily test uncore patches. Sorry I should mention that. sysfs is the final solution, but I'm not clear how the sysfs structures should be. As we discussed before, 1. Should we list all events under sysfs? /sys/devices/system/cpu/cpuN/events/event0 ... /sys/devices/system/cpu/cpuN/events/eventN /sys/devices/system/node/nodeN/pmuN/events/event0 ... /sys/devices/system/node/nodeN/pmuN/events/eventN 2. Or should we use a sysfs file to pass in raw config value? /sys/devices/system/cpu/cpuN/raw /sys/devices/system/node/nodeN/pmuN/raw? 3. How will the additional attributes(needed by IBM PowerEN chip, etc) be passed in? 4. and other problems I don't remember now. > > - Corey