From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756072AbZDXKW4 (ORCPT ); Fri, 24 Apr 2009 06:22:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753338AbZDXKWr (ORCPT ); Fri, 24 Apr 2009 06:22:47 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:56035 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752169AbZDXKWr (ORCPT ); Fri, 24 Apr 2009 06:22:47 -0400 Date: Fri, 24 Apr 2009 11:23:48 +0100 From: Alan Cox To: Rutkov Denis Cc: linux-kernel@vger.kernel.org Subject: Re: High kernel CPU usage when copying files Message-ID: <20090424112348.64fb5c73@lxorguk.ukuu.org.uk> In-Reply-To: References: X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Whenever I copy files I got very high CPU usage from kernel. I tested this with ext3, ext4 and fat32 file systems. To trace the problem I installed oprofile and debug kernel image. I ran the profiler during file copying and saw that there are many calls to copy_to_user_ll and copy_from_user_ll functions. So I have two questions: > > 1. Is this normal I get so many of those function calls? Yes > 2. What can I do to further trace this bug? Are you seeing high CPU usage or just a lot of D state processes (blocked waiting I/O) ? Alan