From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753315Ab0LFO66 (ORCPT ); Mon, 6 Dec 2010 09:58:58 -0500 Received: from one.firstfloor.org ([213.235.205.2]:54211 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750709Ab0LFO65 (ORCPT ); Mon, 6 Dec 2010 09:58:57 -0500 Date: Mon, 6 Dec 2010 15:58:52 +0100 From: Andi Kleen To: "Ted Ts'o" , Andi Kleen , David Sharp , rostedt@goodmis.org, linux-kernel@vger.kernel.org, mrubin@google.com Subject: Re: [Patch 00/15] Reduce tracing payload size. Message-ID: <20101206145852.GA24977@basil.fritz.box> References: <1291421609-14665-1-git-send-email-dhsharp@google.com> <878w03t4sn.fsf@basil.nowhere.org> <20101206135637.GC8135@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101206135637.GC8135@thunk.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 06, 2010 at 08:56:37AM -0500, Ted Ts'o wrote: > On Mon, Dec 06, 2010 at 02:22:00PM +0100, Andi Kleen wrote: > > David Sharp writes: > > > > > > These patches are just a start to shrinking the size of trace events. I am > > > planning to also make small versions of trace events that are used when > > > CONFIG_SMALL_TRACES is enabled. I'm also open to discussion of other ways to > > > shrink event sizes. > > > > Maybe the simplest would be to lzo them as they get logged? > > I assume you already considered that? > > The tracing subsystem is supposed to be extremely low-overhead. > Compressiong the event log would add considerable CPU overhead. If we lzo as a rule of thumb is about as expensive as 3x memcpy() That's not really expensive. -Andi -- ak@linux.intel.com -- Speaking for myself only.