From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q92JjvXp081960 for ; Tue, 2 Oct 2012 14:45:58 -0500 Received: from moltke.seatribe.se (moltke.seatribe.se [178.63.100.209]) by cuda.sgi.com with ESMTP id gfDRkWlIMIJKtx7O (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Tue, 02 Oct 2012 12:47:20 -0700 (PDT) Date: Tue, 2 Oct 2012 16:31:48 +0200 (CEST) From: Fredrik Tolf Subject: Re: Extreme I/O latency In-Reply-To: <20121002050806.GO23520@dastard> Message-ID: References: <20121002022041.GN23520@dastard> <20121002050806.GO23520@dastard> MIME-Version: 1.0 List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: xfs@oss.sgi.com On Tue, 2 Oct 2012, Dave Chinner wrote: > On Tue, Oct 02, 2012 at 05:25:53AM +0200, Fredrik Tolf wrote: >> On Tue, 2 Oct 2012, Dave Chinner wrote: >>> On Tue, Oct 02, 2012 at 03:53:08AM +0200, Fredrik Tolf wrote: >>> What is a "simple IO operation"? >> >> Sorry, what I meant by "simple" is mostly on the interface level. >> Like, a single syscall (with far less than a page of data in the >> case of read or write), or, in this case, reading a single mmap'ed >> page. > > Which might be "simple" by themselves, but when an application is > doing thousands of such operations a second, the result is far from > simple.... Certainly; though I seem to be bad at communicating it, the point I was trying to make is that it is, from the point of view of userspace, individual calls that take extremely long, rather than total throughput being poor. :) -- Fredrik Tolf _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs