From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263904AbUCZCKu (ORCPT ); Thu, 25 Mar 2004 21:10:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263906AbUCZCKt (ORCPT ); Thu, 25 Mar 2004 21:10:49 -0500 Received: from palrel12.hp.com ([156.153.255.237]:59039 "EHLO palrel12.hp.com") by vger.kernel.org with ESMTP id S263904AbUCZCKl (ORCPT ); Thu, 25 Mar 2004 21:10:41 -0500 From: David Mosberger MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16483.37151.114594.263358@napali.hpl.hp.com> Date: Thu, 25 Mar 2004 18:10:39 -0800 To: Andrew Morton Cc: davidm@hpl.hp.com, davidm@napali.hpl.hp.com, mpm@selenic.com, linux-kernel@vger.kernel.org Subject: Re: Fw: potential /dev/urandom scalability improvement In-Reply-To: <20040325180014.29e40b65.akpm@osdl.org> References: <20040325141923.7080c6f0.akpm@osdl.org> <20040325224726.GB8366@waste.org> <16483.35656.864787.827149@napali.hpl.hp.com> <20040325180014.29e40b65.akpm@osdl.org> X-Mailer: VM 7.18 under Emacs 21.3.1 Reply-To: davidm@hpl.hp.com X-URL: http://www.hpl.hp.com/personal/David_Mosberger/ Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >>>>> On Thu, 25 Mar 2004 18:00:14 -0800, Andrew Morton said: Andrew> We may as well stick prefetch_range() in prefetch.h. Fair enough. Andrew> And Matt's patch series is not a thing I want to take on Andrew> board at present, so let's stick with the straight Andrew> scalability patch for now. Andrew> I moved the prefetch_range() call to outside the spinlock. Andrew> Does that make sense? The other CPUs will dirty that data, so prefetching it before you hold the lock is almost certainly bad for performance. (Well, to be precise, it really depends on the number of lines dirtied.) --david