From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757871Ab0J1Ak5 (ORCPT ); Wed, 27 Oct 2010 20:40:57 -0400 Received: from thunk.org ([69.25.196.29]:51541 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757711Ab0J1Akx (ORCPT ); Wed, 27 Oct 2010 20:40:53 -0400 Date: Wed, 27 Oct 2010 20:40:47 -0400 From: "Ted Ts'o" To: David Daney Cc: Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org Subject: Re: Perf can't deal with many tracepoints Message-ID: <20101028004047.GH3194@thunk.org> Mail-Followup-To: Ted Ts'o , David Daney , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org References: <4CC8C0D2.7060304@caviumnetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CC8C0D2.7060304@caviumnetworks.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on thunker.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 27, 2010 at 05:16:18PM -0700, David Daney wrote: > Tracing is supposed to be low overhead. Forcing people to decode > things like this at the trace point, may take more code and cause > the trace data to be larger, making it slower than necessary. > > If there isn't a good reason to keep perf stupid, then making it > smarter could be attractive. Agreed. Although one argument against making perf smarter is that certain things such as the dev_t MAJOR/MINOR split is an internal abstraction that could potentially vary from kernel to kernel. And the question is whether perf really should be so different that if you boot a different kernel, you had better have the right perf installed. - Ted