Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754125AbZFZHBc (ORCPT ); Fri, 26 Jun 2009 03:01:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750887AbZFZHBY (ORCPT ); Fri, 26 Jun 2009 03:01:24 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:54790 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750747AbZFZHBY (ORCPT ); Fri, 26 Jun 2009 03:01:24 -0400 Subject: Re: register_timer_hook use in arch/sh/oprofile From: Peter Zijlstra To: Ingo Molnar Cc: Paul Mundt , Martin Schwidefsky , linux-kernel In-Reply-To: <20090624132447.GD6224@elte.hu> References: <20090624131104.705c828d@skybase> <20090624112929.GB2079@linux-sh.org> <20090624142828.7c6a2337@skybase> <20090624123416.GB9510@linux-sh.org> <20090624124542.GB32306@elte.hu> <20090624131440.GA9700@linux-sh.org> <20090624132447.GD6224@elte.hu> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Fri, 26 Jun 2009 09:01:25 +0200 Message-Id: <1245999685.31755.157.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 716 Lines: 17 On Wed, 2009-06-24 at 15:24 +0200, Ingo Molnar wrote: > > [ And long-term analysis ('perf stat' type of runs) dont need IRQs > anyway - perfcounters reads outs the counts and summarizes them > across the measured workload. ] If the counter width is less than 64 bits we do need to have some interrupt to read them from before they cycle so we can accumulate the deltas into a proper u64. But for proper 64 bit hardware counters there is indeed no need for that. -- 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/