Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262907AbUC2Mci (ORCPT ); Mon, 29 Mar 2004 07:32:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262896AbUC2McV (ORCPT ); Mon, 29 Mar 2004 07:32:21 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.31.123]:45455 "EHLO atrey.karlin.mff.cuni.cz") by vger.kernel.org with ESMTP id S262907AbUC2MaQ (ORCPT ); Mon, 29 Mar 2004 07:30:16 -0500 Date: Mon, 29 Mar 2004 13:42:10 +0200 From: Pavel Machek To: Jeff Garzik Cc: Bartlomiej Zolnierkiewicz , Stefan Smietanowski , linux-ide@vger.kernel.org, Linux Kernel , Andrew Morton Subject: Re: [PATCH] speed up SATA Message-ID: <20040329114210.GF1453@openzaurus.ucw.cz> References: <4066021A.20308@pobox.com> <40660877.3090302@stesmi.com> <200403280032.22180.bzolnier@elka.pw.edu.pl> <40660FEC.8080703@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <40660FEC.8080703@pobox.com> User-Agent: Mutt/1.3.27i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 914 Lines: 23 Hi! > >What about latency? ... > merged transfer will top out at 8MB. You don't see that unless > you're on a totally quiet machine with tons of free, contiguous > pages. So in practice it winds up being much smaller, the more > loaded the system gets (and pagecache gets fragmented). > > Latency definitely changes for the default case, but remember that a > lot of that is writeback, or streaming writes. Latency-sensitive > applications already know how to send small or no-wait I/Os, because Well, waiting second for read because 32MB write is being done will not be fun... -- 64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms - 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/