Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S942076AbcJ1Pne (ORCPT <rfc822;w@1wt.eu>);
        Fri, 28 Oct 2016 11:43:34 -0400
Received: from foss.arm.com ([217.140.101.70]:33898 "EHLO foss.arm.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1760585AbcJ1Pnd (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 28 Oct 2016 11:43:33 -0400
Date: Fri, 28 Oct 2016 16:42:59 +0100
From: Mark Rutland <mark.rutland@arm.com>
To: Jan Glauber <jan.glauber@caviumnetworks.com>
Cc: Will Deacon <will.deacon@arm.com>,
        Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 0/5] Cavium ThunderX uncore PMU support
Message-ID: <20161028154259.GM5806@leverpostej>
References: <1476955841-27898-1-git-send-email-jglauber@cavium.com>
 <20161020103707.GB3175@twins.programming.kicks-ass.net>
 <20161020112351.GC13708@hardcore>
 <20161028151749.GG14402@arm.com>
 <20161028153646.GA11371@hardcore>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20161028153646.GA11371@hardcore>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1721
Lines: 35

On Fri, Oct 28, 2016 at 05:36:46PM +0200, Jan Glauber wrote:
> On Fri, Oct 28, 2016 at 04:17:49PM +0100, Will Deacon wrote:
> > On Thu, Oct 20, 2016 at 01:23:51PM +0200, Jan Glauber wrote:
> > > On Thu, Oct 20, 2016 at 12:37:07PM +0200, Peter Zijlstra wrote:
> > > > On Thu, Oct 20, 2016 at 11:30:36AM +0200, Jan Glauber wrote:
> > > > > Note:
> > > > > I'm using perf_sw_context in difference to perf_invalid_context
> > > > > (see WARN_ON in perf_pmu_register). Reason is that with perf_invalid_context
> > > > > add() is never called and the counter results are shown as "unsupported" by
> > > > > perf. With perf_sw_context everything works as expected.
> > > > 
> > > > What?! All the uncore PMUs use perf_invalid_context. What doesn't work
> > > > for you?
> > > 
> > > OK, so using perf_invalid_context and "-a" seems to work.
> > > 
> > > But I must say that I hate that from a user perspective. The user needs to know about
> > > the type of PMU behind the event and then provide "-a" or get a "<not supported"
> > > as counter value?
> > 
> > Sure, but in the interest of getting *something* merged, can we start
> > off using perf_invalid_context and then have the discussion about whether
> > or not this can be extended later on, please? If your PMU is a shared
> > resource amongst CPUs, it maybe that all you want is a better error
> > message from the perf tool (but again, this can come later!).
> 
> If that is the only obstacle I can repost with perf_sw_context (or do a
> follow-up patch). After all it works, it is just "clueless" people like
> me that are not aware of the required switches.

Please send a version using perf_invalid_context (which I assume is what
you meant above).

Thanks,
Mark.