Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753236Ab0FZJ2Q (ORCPT ); Sat, 26 Jun 2010 05:28:16 -0400 Received: from verein.lst.de ([213.95.11.210]:46420 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752245Ab0FZJ2O (ORCPT ); Sat, 26 Jun 2010 05:28:14 -0400 Date: Sat, 26 Jun 2010 11:27:59 +0200 From: Christoph Hellwig To: Nick Piggin Cc: Christoph Hellwig , Vivek Goyal , Jens Axboe , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: trying to understand READ_META, READ_SYNC, WRITE_SYNC & co Message-ID: <20100626092759.GA25896@lst.de> References: <20100621094828.GA30748@lst.de> <4C1F3916.4070608@kernel.dk> <20100621110436.GA4056@lst.de> <4C1FB5F7.3070908@kernel.dk> <20100621191410.GA24213@lst.de> <20100621213618.GC6474@redhat.com> <20100623100138.GA9575@lst.de> <20100624014420.GB3297@redhat.com> <20100625110319.GA12855@lst.de> <20100626092556.GH29809@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100626092556.GH29809@laptop> User-Agent: Mutt/1.3.28i X-Spam-Score: 0 () Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 847 Lines: 15 On Sat, Jun 26, 2010 at 07:25:56PM +1000, Nick Piggin wrote: > Biggest thing is multiple small files operations like on the same > directory. Best case I measured back when doing AS io scheduler > versus deadline was about 100x improvement on a uncached kernel > grep workload when competing with a streaming writeout (the writeout > probably ended up going somewhat slower naturally, but it is fairer). As I mentioned below I absolutely see the case for reads. A normal grep basically is a dependent read kind of workload. For for writes it should either be O_SYNC-style workloads or batched I/O. -- 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/