From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754160Ab2BAAs3 (ORCPT ); Tue, 31 Jan 2012 19:48:29 -0500 Received: from e33.co.us.ibm.com ([32.97.110.151]:33945 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752541Ab2BAAs2 (ORCPT ); Tue, 31 Jan 2012 19:48:28 -0500 Message-ID: <4F288BBC.9080202@linux.vnet.ibm.com> Date: Tue, 31 Jan 2012 16:47:56 -0800 From: Corey Ashford User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0.1 MIME-Version: 1.0 To: Peter Zijlstra CC: Jiri Olsa , acme@redhat.com, mingo@elte.hu, paulus@samba.org, linux-kernel@vger.kernel.org, Carl Love Subject: Re: [PATCH 5/9] perf: Adding sysfs group format attribute for pmu device References: <1326717103-10287-1-git-send-email-jolsa@redhat.com> <1327674868-10486-1-git-send-email-jolsa@redhat.com> <1327674868-10486-6-git-send-email-jolsa@redhat.com> <4F231256.8080905@linux.vnet.ibm.com> <1327699182.2446.177.camel@twins> In-Reply-To: <1327699182.2446.177.camel@twins> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12020100-2398-0000-0000-000003D6F962 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/27/2012 01:19 PM, Peter Zijlstra wrote: > On Fri, 2012-01-27 at 13:08 -0800, Corey Ashford wrote: >> s an example, the IBM PowerEN processor has roughly 20 different PMU's >> on it. Some of those PMU's are quite complex and divide their events up >> into subsets, each with different fields. For example, some events may >> have a PID matching field, and others may have an bus number matching >> field, or matching mode field, etc. The fields are different widths, >> and may overlap in the config/1/2 space. >> >> It seems that there are two approaches you could take: >> >> 1) Keep your format, but allow the fields to overlap in the bit space. >> For example: >> >> "/sys/.../format/event" contains "config:0-7" >> "/sys/.../format/pidmatch" contains "config:8-15" >> "/sys/.../format/busmatch" contains "config:8-13" >> >> Note that busmatch overlaps pidmatch >> >> 2) Create event groups that have their overlapping config space >> separated out: >> >> "/sys/.../format/event" contains "config:0-7" >> >> "/sys/....1/format/pidmatch" contains "config:8-15" >> >> "/sys/....2/format/busmatch" contains "config:8-13" >> >> >> Notice the .1 and .2 on the . >> >> This might help the user understand which fields go together. I'm not >> sold on the .1 syntax... you could do it as ./ or >> //... or whatever seems to make the most sense >> and is relatively easy to implement and use. > > Why try and stuff those 20 in a single driver? Have 20 drivers and each > their own format/ hierarchy. I'm sure that could work. Since sysfs seems to be fairly independent (if necessary) of the hardware structure, I suppose this wouldn't be a problem. What do you think of Jiri's (Jirka's ?) other ideas of subdividing the format directory? - Corey