Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262644AbVCJBWa (ORCPT ); Wed, 9 Mar 2005 20:22:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262603AbVCJBVb (ORCPT ); Wed, 9 Mar 2005 20:21:31 -0500 Received: from fmr22.intel.com ([143.183.121.14]:27856 "EHLO scsfmr002.sc.intel.com") by vger.kernel.org with ESMTP id S262444AbVCJA5m (ORCPT ); Wed, 9 Mar 2005 19:57:42 -0500 Message-Id: <200503100057.j2A0v6g27712@unix-os.sc.intel.com> From: "Chen, Kenneth W" To: "'Andi Kleen'" Cc: , Subject: RE: Direct io on block device has performance regression on 2.6.x kernel Date: Wed, 9 Mar 2005 16:57:06 -0800 X-Mailer: Microsoft Office Outlook, Build 11.0.6353 Thread-Index: AcUk/vcXB6PKjh7PRESRQ5g7oVIo7wADM0RQ In-Reply-To: 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: 865 Lines: 21 Andi Kleen wrote on Wednesday, March 09, 2005 3:23 PM > > Just to clarify here, these data need to be taken at grain of salt. A > > high count in _spin_unlock_* functions do not automatically points to > > lock contention. It's one of the blind spot syndrome with timer based > > profile on ia64. There are some lock contentions in 2.6 kernel that > > we are staring at. Please do not misinterpret the number here. > > Why don't you use oprofile?>? It uses NMIs and can profile "inside" > interrupt disabled sections. The profile is taken on ia64. we don't have nmi. Oprofile will produce the same result. - 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/