From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751975Ab3F0DS7 (ORCPT ); Wed, 26 Jun 2013 23:18:59 -0400 Received: from ozlabs.org ([203.10.76.45]:34579 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751673Ab3F0DS5 (ORCPT ); Wed, 26 Jun 2013 23:18:57 -0400 Date: Thu, 27 Jun 2013 13:18:54 +1000 From: Michael Ellerman To: Andi Kleen Cc: mingo@elte.hu, acme@redhat.com, linux-kernel@vger.kernel.org, Andi Kleen , mlpesant@us.ibm.com Subject: Re: [PATCH 15/15] perf, tools: Add perf stat --transaction v3 Message-ID: <20130627031854.GA9793@concordia> References: <1366485563-16209-1-git-send-email-andi@firstfloor.org> <1366485563-16209-16-git-send-email-andi@firstfloor.org> <20130619085159.GA25177@concordia> <20130619144621.GW6123@two.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130619144621.GW6123@two.firstfloor.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 19, 2013 at 04:46:21PM +0200, Andi Kleen wrote: > > This hard coded list isn't going to work for us on powerpc. > > > > We don't have HLE, so we won't ever have an event for el-start. > > > > I don't quite grok what the cycles-ct is about, checkpointed cycles? > > The counter is check pointed on a transaction start, and set back to > the checkpoint when an abort happens. This allows to count the cycles > wasted in aborts, when you subtract from cycles-t. OK. I'm still confused by that one sorry. In the patch you do: + else if (perf_evsel__cmp(counter, nth_evsel(T_CYCLES_IN_TX_CP))) + update_stats(&runtime_cycles_in_txcp_stats[0], count[0]); But then I don't see where you use runtime_cycles_in_txcp_stats ? > > But I don't think we have anything equivalent. > > But you have cycles-t and tx-start? We have: - cycles - cycles in transactional state - cycles spent in successful transactions So your cycles-t is "cycles in transactional state". We would calculate cycles wasted in aborts with: "cycles in transactional" - "cycles in successful transactions" Which I think is what you're describing above with cycles-ct. Does "tx-start" just count the number of transactions begun? Does it count nested transactions? We have one counter for non-nested transactions and one for nested, but I think we could just count the non-nested as "tx-start", that's probably of most interest. > > I guess the simplest option is to make it a per-arch list inside the > > perf tool? > > I'm not sure that would be acceptable to the perf maintainers. > Although I'm just guessing, I haven't heard any comments on > this patch recently. Yeah sure. Although I agree with the desire to make the perf tool work similarly across architectures, I think as we add more of these detailed analysis tools we are eventually going to come across something that can't be handled generically. But I guess we'll see. cheers