Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753227AbaKQVYN (ORCPT ); Mon, 17 Nov 2014 16:24:13 -0500 Received: from e37.co.us.ibm.com ([32.97.110.158]:39915 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752064AbaKQVYM (ORCPT ); Mon, 17 Nov 2014 16:24:12 -0500 Date: Mon, 17 Nov 2014 13:24:00 -0800 From: Sukadev Bhattiprolu To: Alexander Shishkin Cc: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, Robert Richter , Frederic Weisbecker , Mike Galbraith , Paul Mackerras , Stephane Eranian , Andi Kleen , kan.liang@intel.com, adrian.hunter@intel.com, markus.t.metzger@intel.com, mathieu.poirier@linaro.org, acme@infradead.org, Peter Zijlstra , Michael Ellerman Subject: Re: [PATCH v8 02/14] perf: Add AUX area to ring buffer for raw data streams Message-ID: <20141117212400.GB13111@us.ibm.com> References: <1415972627-37514-1-git-send-email-alexander.shishkin@linux.intel.com> <1415972627-37514-3-git-send-email-alexander.shishkin@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1415972627-37514-3-git-send-email-alexander.shishkin@linux.intel.com> X-Operating-System: Linux 2.0.32 on an i486 User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14111721-0025-0000-0000-0000062C5EA7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alexander Shishkin [alexander.shishkin@linux.intel.com] wrote: | From: Peter Zijlstra | | This patch introduces "AUX space" in the perf mmap buffer, intended for | exporting high bandwidth data streams to userspace, such as instruction | flow traces. | | AUX space is a ring buffer, defined by aux_{offset,size} fields in the | user_page structure, and read/write pointers aux_{head,tail}, which abide | by the same rules as data_* counterparts of the main perf buffer. The "format" of this raw stream of data can differ across processors (and architecutres) correct ? i.e the perf tool processing of this aux data will also differ across processors ? Power8 processors support what we call 24x7 counters that collect info on a large number of events. The current 24x7 support in (arch/powerpc/perf/hv-24x7.c) currently uses reading one counter at a time using the pmu->read() interface. We are looking for ways to export much larger number of counters through one pmu->read() or another call. I am trying to see if the hv-24x7 pmu could use this aux interface and then have/implement a helper in perf tool to extract the counter values. Sukadev -- 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/