From owner-freebsd-hackers Tue Nov 10 22:54:56 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id WAA09578 for freebsd-hackers-outgoing; Tue, 10 Nov 1998 22:54:56 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from gatekeeper.whistle.com (gatekeeper.whistle.com [207.76.204.2]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id WAA09573 for ; Tue, 10 Nov 1998 22:54:55 -0800 (PST) (envelope-from julian@whistle.com) Received: (from smap@localhost) by gatekeeper.whistle.com (8.8.8/8.8.7) id VAA23921 for ; Tue, 10 Nov 1998 21:08:55 -0800 (PST) (envelope-from julian@whistle.com) Received: from alpo.whistle.com(unknown 207.76.204.38) by gatekeeper.whistle.com via smap (V2.0) id xma023919; Tue, 10 Nov 98 21:08:53 -0800 Received: (from daemon@localhost) by alpo.whistle.com (8.8.5/8.8.5) id UAA26748; Tue, 10 Nov 1998 20:54:46 -0800 (PST) Received: from current1.whistle.com(207.76.205.22) via SMTP by alpo.whistle.com, id smtpdl26745; Wed Nov 11 04:54:38 1998 Date: Tue, 10 Nov 1998 20:54:05 -0800 (PST) From: Julian Elischer To: Greg Lehey cc: Peter Jeremy , hackers@FreeBSD.ORG Subject: Re: SCSI tagged queueing and softupdates In-Reply-To: <19981111151628.J20374@freebie.lemis.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, 11 Nov 1998, Greg Lehey wrote: > On Tuesday, 10 November 1998 at 20:16:08 -0800, Julian Elischer wrote: > > > Soft updates will not schedule any IO that depends on an uncompleted IO > > operation. So therefore all operations that have been 'passed to the > > driver' are not dependent on each other (by definition) > > Doesn't this slow the whole thing down? Or is that what's behind > B_ORDERED? Softupdates doesn't use B_ORDERED no, it can write out a directory block even if there are uncompleted inode writes it is waiting on... it fabricates a directory block with those entries, marked as invalid and writes out that copy instead. When the inode writes are completed, it will schedule a rewrite to the disk of the completed block. it's incredibally sneaky that way.. same for inodes. etc. > > Greg > -- > See complete headers for address, home page and phone numbers > finger grog@lemis.com for PGP public key > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message