From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 8 Jul 2002 08:30:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 8 Jul 2002 08:30:41 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:11276 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Mon, 8 Jul 2002 08:30:40 -0400 Date: Mon, 8 Jul 2002 13:33:21 +0100 From: Matthew Wilcox To: Alexander Viro Cc: Dave Hansen , Matthew Wilcox , Oliver Neukum , Thunder from the hill , Greg KH , kernel-janitor-discuss , linux-kernel@vger.kernel.org Subject: Re: BKL removal Message-ID: <20020708133321.S27706@parcelfarce.linux.theplanet.co.uk> References: <3D28FE72.1080603@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from viro@math.psu.edu on Sun, Jul 07, 2002 at 11:06:32PM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 07, 2002 at 11:06:32PM -0400, Alexander Viro wrote: > The thing being, if you are already contended you are playing "I'll release > CPU now" vs. "I'll spin in hope that contender will go away right now". > > IOW, it's a win only if you get contention often and for short intervals. > Which is a very good indication that something is rotten with your locking > scheme. Like, say it, having lost the control over the amount of locks > as the result of brainde^Woverenthusiastic belief that fine-grained == > good. With everything that follows from that... So let's get some numbers. It really shouldn't be hard to make our current semaphores spin a little before they sleep. If we get some numbers showing it does help then either we need this change in mainline or we need to fix our locking. -- Revolutions do not require corporate support.