From: Linus Torvalds Subject: Re: [RFC, PATCH] Avoid hot statistics cache line in ext4 extent cache Date: Fri, 13 Apr 2012 11:08:20 -0700 Message-ID: References: <20120323221715.GA6712@tassilo.jf.intel.com> <20120324031357.GA5690@tassilo.jf.intel.com> <4F70F51F.8030405@linux.intel.com> <20120326235707.GC19489@thunk.org> <1334339612.3796.2.camel@schen9-DESK> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Andi Kleen , "Ted Ts'o" , Vivek Haldar , Andreas Dilger , linux-ext4@vger.kernel.org To: Tim Chen Return-path: Received: from mail-wi0-f172.google.com ([209.85.212.172]:40856 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752816Ab2DMSIm (ORCPT ); Fri, 13 Apr 2012 14:08:42 -0400 Received: by wibhj6 with SMTP id hj6so6766940wib.1 for ; Fri, 13 Apr 2012 11:08:41 -0700 (PDT) In-Reply-To: <1334339612.3796.2.camel@schen9-DESK> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Apr 13, 2012 at 10:53 AM, Tim Chen wrote: >> >> Do you have numbers? > > In a benchmark that does mmaped-read, there is a 28% speed up > after getting rid of the counters. Ok, that's big. But is it any actual real workload on a real filesystem? It looks like this should only happen for actual IO, so I get the feeling that this is some made-up benchmark for a filesystem on a RAM-disk? Linus