Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751258AbWAVOYH (ORCPT ); Sun, 22 Jan 2006 09:24:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751267AbWAVOYG (ORCPT ); Sun, 22 Jan 2006 09:24:06 -0500 Received: from mx.freeshell.ORG ([192.94.73.21]:16086 "EHLO sdf.lonestar.org") by vger.kernel.org with ESMTP id S1751258AbWAVOYF (ORCPT ); Sun, 22 Jan 2006 09:24:05 -0500 From: Jim Nance Date: Sun, 22 Jan 2006 14:24:01 +0000 To: Jon Smirl Cc: lkml Subject: Re: sendfile() with 100 simultaneous 100MB files Message-ID: <20060122142401.GA24738@SDF.LONESTAR.ORG> References: <9e4733910601201353g36284133xf68c4f6eae1344b4@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9e4733910601201353g36284133xf68c4f6eae1344b4@mail.gmail.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1177 Lines: 31 On Fri, Jan 20, 2006 at 04:53:44PM -0500, Jon Smirl wrote: > Any other ideas why sendfile() would get into a seek storm? I can't really comment on the quality of the linux sendfile() implementation, I've never looked at the code. However, a couple of general observations. The seek storm happens because linux is trying to be "fair," where fair means no one process get to starve another for I/O bandwidth. The fastest way to transfer 100 100M files would be to send them one at a time. The 99th person in line of course would percieve this as a very poor implementation. The current sendfile implementation seems to live at the other end of the extream. It is possible to come up with a compromise behavior by limiting the number of concurrent sendfiles running, and the maximum size they are allowed to send in one squirt. Thanks, Jim -- jlnance@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org - 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/