Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753331Ab0BIGyp (ORCPT ); Tue, 9 Feb 2010 01:54:45 -0500 Received: from mail-qy0-f200.google.com ([209.85.221.200]:57300 "EHLO mail-qy0-f200.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751634Ab0BIGyo (ORCPT ); Tue, 9 Feb 2010 01:54:44 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=dxY94WnbFdZTMTXqEsf+T+M6G9DEyJgvDK5Hazunc90kdV+OC6Ddcc4yk17tGS60kP ltPlpd8N9WlaMMQfYLML4mmM+uauq7++LE4eNIl3bnNjjqFDO4TYeWagYuux6G+lpZMU A3GxLrjg/o7zypOOm+c9p0MOp5cheun7zhv6A= MIME-Version: 1.0 In-Reply-To: <20100209041739.GA11280@elte.hu> References: <20100208184504.GB5130@lenovo> <20100209041739.GA11280@elte.hu> Date: Tue, 9 Feb 2010 09:54:43 +0300 Message-ID: Subject: Re: [RFC perf,x86] P4 PMU early draft From: Cyrill Gorcunov To: Ingo Molnar Cc: Peter Zijlstra , Stephane Eranian , Frederic Weisbecker , Don Zickus , LKML Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1784 Lines: 51 On 2/9/10, Ingo Molnar wrote: > > * Cyrill Gorcunov wrote: > >> Hi all, >> >> first of all the patches are NOT for any kind of inclusion. It's not ready >> >> yet. More likely I'm asking for glance review, ideas, criticism. > > A quick question: does the code produce something on a real P4? (possibly > only running with a single event - but even that would be enough.) not yet, a few code snippets need to be added into scheduling routine, hope to finish this today evening > >> The main problem in implementing P4 PMU is that it has much more >> restrictions for event to MSR mapping. [...] > > One possibly simpler approach might be to represent the P4 PMU via a maximum > _two_ generic events only. > yeah, good idea! > Last i looked at the many P4 events, i've noticed that generally you can > create any two events. (with a few exceptions) Once you start trying to take > advantage of the more than a dozen seemingly separate counters, additional > non-trivial constraints apply. > > So if we only allowed a maximum of _two_ generic events (like say a simple > Core2 has, so it's not a big restriction at all), we wouldnt have to map all > the constraints, we'd only have to encode the specific event-to-MSR details. > (which alone is quite a bit of work as well.) > > We could also use the new constraints code to map them all, of course - it > will certainly be more complex to implement. > i thought about it, but i didn't like the result code ;) will think about it. > Hm? > > Ingo > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/