Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 26 Oct 2002 03:47:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 26 Oct 2002 03:47:12 -0400 Received: from ns.suse.de ([213.95.15.193]:46086 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id ; Sat, 26 Oct 2002 03:47:11 -0400 To: Rob Landley Cc: linux-kernel@vger.kernel.org Subject: Re: The return of the return of crunch time (2.5 merge candidate list 1.6) References: <200210251557.55202.landley@trommello.org.suse.lists.linux.kernel> From: Andi Kleen Date: 26 Oct 2002 09:53:26 +0200 In-Reply-To: Rob Landley's message of "26 Oct 2002 04:01:47 +0200" Message-ID: X-Mailer: Gnus v5.7/Emacs 20.6 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1643 Lines: 30 Rob Landley writes: I have some patches to offer better than second resolution for stat. That is needed for parallel make on MP systems, because otherwise it cannot detect changes that need less than a second to execute. With CPUs being as fast as they are and getting even faster currently it is becomming a bigger problem. You don't hit it that easily with gcc because it's getting faster slower than cpus are getting faster so it's usually slower than a second, but some people use make rules with other compilers or other commands. I see it in the same category as "necessary changes" similar to 32bit dev_t. Linux already has several filesystems in tree that support ns or better than s resolution in their underlying formats (XFS,JFS,NFSv3,VFAT) Patches available on request or older versions from ftp://ftp.firstfloor.org/pub/ak/v2.5/nsec* They don't actually add ns resolution, but jiffies resolution, which is 1ms on 2.5 and should be good enough for now. It reuses reserved fields in struct stat and doesn't need any user interface changes. It requires editing of a lot of file systems in a straight forward way, so should be better done before the stable series starts. There are some minor compatbility issues with fs that only support second timestamps like ext2/ext3, see nsec.notes in the ftp directory or past threads on that on the list. -Andi - 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/