From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756056Ab2IGTJE (ORCPT ); Fri, 7 Sep 2012 15:09:04 -0400 Received: from casper.infradead.org ([85.118.1.10]:41301 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751342Ab2IGTJA convert rfc822-to-8bit (ORCPT ); Fri, 7 Sep 2012 15:09:00 -0400 Message-ID: <1347044931.2124.5.camel@twins> Subject: Re: [PATCH 1/3] perf: use hrtimer for event multiplexing From: Peter Zijlstra To: Stephane Eranian Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, ak@linux.intel.com, zheng.z.yan@intel.com, robert.richter@amd.com Date: Fri, 07 Sep 2012 21:08:51 +0200 In-Reply-To: References: <1347028169-1983-1-git-send-email-eranian@google.com> <1347028169-1983-2-git-send-email-eranian@google.com> <1347032350.18408.88.camel@twins> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2012-09-07 at 19:03 +0200, Stephane Eranian wrote: > I think having different intervals would be a good thing, especially for uncore. > But now, I am wondering how this could work without too much overhead. > Looks like you're suggesting arming multiple hrtimers if multiple PMU are > overcommitted. Is that right? Right, we shoulnd't have too many PMUs anyway, let alone over committed ones, so a timer per cpu per pmu should be fine. > As opposed to having a PMU multiplier off of a > single per-cpu hrtimer.