Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753846Ab0LFQbH (ORCPT ); Mon, 6 Dec 2010 11:31:07 -0500 Received: from mail-yx0-f174.google.com ([209.85.213.174]:62098 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753755Ab0LFQbF convert rfc822-to-8bit (ORCPT ); Mon, 6 Dec 2010 11:31:05 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=V6FTCyU3P0iHZMcbOB/aVJ7v7oAV7f3ezMs2unz+xg9EJqlGkGZKK66XmcbKqfDg+r gas95f30idNJmRrGOZ268PE/zIB/iT4Gw0P6gGsSY20OWEiONcBiLYgsBf0uwuLaV+tv 0ifg8hw4zkckufpfg3FmkgatWOK5v3Hqf8U8E= MIME-Version: 1.0 In-Reply-To: <20101206145852.GA24977@basil.fritz.box> References: <1291421609-14665-1-git-send-email-dhsharp@google.com> <878w03t4sn.fsf@basil.nowhere.org> <20101206135637.GC8135@thunk.org> <20101206145852.GA24977@basil.fritz.box> From: Miguel Ojeda Date: Mon, 6 Dec 2010 17:31:04 +0100 Message-ID: Subject: Re: [Patch 00/15] Reduce tracing payload size. To: Andi Kleen Cc: "Ted Ts'o" , David Sharp , rostedt@goodmis.org, linux-kernel@vger.kernel.org, mrubin@google.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1552 Lines: 38 On Mon, Dec 6, 2010 at 3:58 PM, Andi Kleen wrote: > 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. That is true for the decompression step but not for the compression one, which takes more than 10 memcpys(). > > -Andi > > -- > ak@linux.intel.com -- Speaking for myself only. > -- > 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/ > -- 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/