Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262709AbVCJBtc (ORCPT ); Wed, 9 Mar 2005 20:49:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262611AbVCJBrC (ORCPT ); Wed, 9 Mar 2005 20:47:02 -0500 Received: from fmr23.intel.com ([143.183.121.15]:30671 "EHLO scsfmr003.sc.intel.com") by vger.kernel.org with ESMTP id S262718AbVCJBpF (ORCPT ); Wed, 9 Mar 2005 20:45:05 -0500 Message-Id: <200503100144.j2A1isg28121@unix-os.sc.intel.com> From: "Chen, Kenneth W" To: "'Andrew Morton'" Cc: , Subject: RE: Direct io on block device has performance regression on 2.6.x kernel Date: Wed, 9 Mar 2005 17:44:54 -0800 X-Mailer: Microsoft Office Outlook, Build 11.0.6353 Thread-Index: AcUlEUiJXG7NNZKzRr2d0jQxLsIaVQAAIIbw In-Reply-To: <20050309173351.0d69de25.akpm@osdl.org> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 869 Lines: 25 Andrew Morton wrote on Wednesday, March 09, 2005 5:34 PM > What are these percentages? Total CPU time? The direct-io stuff doesn't > look too bad. It's surprising that tweaking the direct-io submission code > makes much difference. Percentage is relative to total kernel time. There are three DIO functions showed up in the profile: __blockdev_direct_IO 4.97% dio_bio_end_io 2.70% dio_bio_complete 1.20% > hm. __blockdev_direct_IO() doesn't actually do much. I assume your damn > compiler went and inlined direct_io_worker() on us. We are using gcc version 3.4.3. I suppose I can finger point gcc ? :-P - Ken - 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/