Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946146AbWKJJWg (ORCPT ); Fri, 10 Nov 2006 04:22:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946148AbWKJJWg (ORCPT ); Fri, 10 Nov 2006 04:22:36 -0500 Received: from brick.kernel.dk ([62.242.22.158]:7797 "EHLO kernel.dk") by vger.kernel.org with ESMTP id S1946146AbWKJJWf (ORCPT ); Fri, 10 Nov 2006 04:22:35 -0500 Date: Fri, 10 Nov 2006 10:24:57 +0100 From: Jens Axboe To: "Chen, Kenneth W" Cc: Brent Baccala , linux-kernel@vger.kernel.org Subject: Re: async I/O seems to be blocking on 2.6.15 Message-ID: <20061110092456.GO4527@kernel.dk> References: <20061105121522.GC13555@kernel.dk> <000001c701e9$a1435260$ff0da8c0@amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000001c701e9$a1435260$ff0da8c0@amr.corp.intel.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 872 Lines: 29 On Mon, Nov 06 2006, Chen, Kenneth W wrote: > I haven't done the measurement whether the time to submit I/O grows > linearly with respect to I/O size. Most likely it will. If it is > not, then we might have a scaling problem (though I don't believe we > have this problem). I would not expect it to, but ran a simple test to check submission times from 32KiB to 2MiB: Size Time (usecs) ---------------------------- 2MiB 223 1MiB 112 512KiB 56 256KiB 29 128KiB 14 32KiB 4 (note that I skipped 64KiB, things got boring). That clearly shows a linear increase in time, so no scaling problem there. -- Jens Axboe - 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/