From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id CA49F6B0105 for ; Tue, 28 Jun 2011 15:40:29 -0400 (EDT) Received: by gyg13 with SMTP id 13so289759gyg.14 for ; Tue, 28 Jun 2011 12:40:26 -0700 (PDT) Message-ID: <4E0A2E26.5000001@gmail.com> Date: Tue, 28 Jun 2011 12:40:22 -0700 From: David Daney MIME-Version: 1.0 Subject: Re: [PATCH] slub: reduce overhead of slub_debug References: <20110626193918.GA3339@joi.lan> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Marcin Slusarz , Pekka Enberg , Matt Mackall , LKML , linux-mm@kvack.org On 06/28/2011 12:32 PM, Christoph Lameter wrote: > On Sun, 26 Jun 2011, Marcin Slusarz wrote: > >> slub checks for poison one byte by one, which is highly inefficient >> and shows up frequently as a highest cpu-eater in perf top. > > Ummm.. Performance improvements for debugging modes? If you need > performance then switch off debuggin. There is no reason to make things gratuitously slow. I don't know about the merits of this particular patch, but I must disagree with the general sentiment. We have high performance tracing, why not improve this as well. Just last week I was trying to find the cause of memory corruption that only occurred at very high network packet rates. Memory allocation speed was definitely getting in the way of debugging. For me, faster SLUB debugging would be welcome. David Daney -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org