From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965099AbVHZXXx (ORCPT ); Fri, 26 Aug 2005 19:23:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965108AbVHZXXx (ORCPT ); Fri, 26 Aug 2005 19:23:53 -0400 Received: from smtp.osdl.org ([65.172.181.4]:47009 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S965099AbVHZXXw (ORCPT ); Fri, 26 Aug 2005 19:23:52 -0400 Date: Fri, 26 Aug 2005 16:23:38 -0700 (PDT) From: Linus Torvalds To: Rik van Riel cc: Hugh Dickins , Nick Piggin , Ray Fucillo , linux-kernel@vger.kernel.org Subject: Re: process creation time increases linearly with shmem In-Reply-To: Message-ID: References: <430CBFD1.7020101@intersystems.com> <430D0D6B.100@yahoo.com.au> <430E6FD4.9060102@yahoo.com.au> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 26 Aug 2005, Rik van Riel wrote: > On Fri, 26 Aug 2005, Hugh Dickins wrote: > > > Well, I still don't think we need to test vm_file. We can add an > > anon_vma test if you like, if we really want to minimize the fork > > overhead, in favour of later faults. Do we? > > When you consider NUMA placement (the child process may > end up running elsewhere), allocating things like page > tables lazily may well end up being a performance win. It should be easy enough to benchmark something like kernel compiles etc, which are reasonably fork-rich and should show a good mix for something like this. Or even just something like "time to restart a X session" after you've brought it into memory once. Linus