From owner-freebsd-hackers Tue Oct 8 13: 3:34 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3CFB837B401 for ; Tue, 8 Oct 2002 13:03:33 -0700 (PDT) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id E500D43E3B for ; Tue, 8 Oct 2002 13:03:32 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.12.5/8.12.4) with ESMTP id g98K3TPQ084533; Tue, 8 Oct 2002 13:03:30 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.12.5/8.12.4/Submit) id g98K3Thx084532; Tue, 8 Oct 2002 13:03:29 -0700 (PDT) (envelope-from dillon) Date: Tue, 8 Oct 2002 13:03:29 -0700 (PDT) From: Matthew Dillon Message-Id: <200210082003.g98K3Thx084532@apollo.backplane.com> To: Don Lewis Cc: olli@secnetix.de, freebsd-hackers@FreeBSD.ORG Subject: Re: Mount option "nomtime"? References: <200210081959.g98JxOvU036374@gw.catspoiler.org> Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :.. :> :> Another example would be "oops", which is a very fast, :> lightweight web proxy. It uses cyclic buffer files to :> store the cached data, similar to INN's CNFS. :> :> I think in the above cases, a "nomtime" option would indeed :> save some unnecessary overhead. : :Probably not much, especially if you are using soft updates. The :in-kernel copy of the inode will get updated on every write, but the :on-disk copy will only get written when the soft updates timer for it :goes off, which I think would be once every 10 seconds and is tunable. I :don't think you'll see much reduction in load compared to all the other :I/O that's going on. atime/mtime/ctime updates will collect in the in-memory inode and only be written to disk when the filesystem sync occurs once every 30-60 seconds or so. This is how it works with or without softupdates. :Noatime won't help much in your examples either. It only buys you a lot :if the data is spread over a large number of files. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message