Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946267AbXBPV0j (ORCPT ); Fri, 16 Feb 2007 16:26:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946270AbXBPV0j (ORCPT ); Fri, 16 Feb 2007 16:26:39 -0500 Received: from mx1.redhat.com ([66.187.233.31]:49967 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946267AbXBPV0i (ORCPT ); Fri, 16 Feb 2007 16:26:38 -0500 Date: Fri, 16 Feb 2007 16:26:31 -0500 From: "Frank Ch. Eigler" To: Andi Kleen Cc: Jeff Muizelaar , linux-kernel@vger.kernel.org Subject: Re: Using sched_clock for mmio-trace Message-ID: <20070216212630.GC27135@redhat.com> References: <20070216013024.GA32287@infidigm.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 853 Lines: 22 Hi - On Fri, Feb 16, 2007 at 09:03:23PM +0100, Andi Kleen wrote: > > We in systemtap land have the same problem, and so far made do with > > slightly postprocessed per-cpu TSC values. > > 90+% likely you're not solving your problem correctly this way. Yes, it was done as a last resort. We need facility that we can call from even more demanding contexts than interrupt handlers, considering that kprobes can be placed nearly anywhere. This is one of the reasons why we don't just use good old do_gettimeofday(), since it takes locks and can lead to lock recursion if parts of itself are probed. - FChE - 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/