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From: Chris Mason <mason@suse.com>
To: James Bottomley <James.Bottomley@steeleye.com>,
	"Stephen C. Tweedie" <sct@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: [PATCH] 2.4.x write barriers (updated for ext3)
Date: Thu, 28 Feb 2002 13:12:40 -0500	[thread overview]
Message-ID: <3903140000.1014919960@tiny> (raw)
In-Reply-To: <3746210000.1014911746@tiny>
In-Reply-To: <200202281536.g1SFaqF02079@localhost.localdomain> <3746210000.1014911746@tiny>



On Thursday, February 28, 2002 10:55:46 AM -0500 Chris Mason <mason@suse.com> wrote:

>> 
>> A longer term solution might be to keep the writeback cache but send down a 
>> SYNCHRONIZE CACHE command as part of the back end completion of a barrier 
>> write, so the fs wouldn't get a completion until the write was done and all 
>> the dirty cache blocks flushed to the medium.
> 
> Right, they could just implement ORDERED_FLUSH in the barrier patch.

So, a little testing with scsi_info shows my scsi drives do have
writeback cache on.  great.  What's interesting is they
must be doing additional work for ordered tags.  If they were treating
the block as written once in cache, using the tags should not change 
performance at all.  But, I can clearly show the tags changing
performance, and hear the drive write pattern change when tags are on.

-chris


  parent reply	other threads:[~2002-02-28 18:19 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-02-22 15:57 [PATCH] 2.4.x write barriers (updated for ext3) James Bottomley
2002-02-22 16:10 ` Chris Mason
2002-02-22 16:13 ` Stephen C. Tweedie
2002-02-22 17:36   ` James Bottomley
2002-02-22 18:14     ` Chris Mason
2002-02-28 15:36       ` James Bottomley
2002-02-28 15:55         ` Chris Mason
2002-02-28 17:58           ` Mike Anderson
2002-02-28 18:12           ` Chris Mason [this message]
2002-03-01  2:08             ` James Bottomley
2002-03-03 22:11         ` Daniel Phillips
2002-03-04  3:34           ` Chris Mason
2002-03-04  5:05             ` Daniel Phillips
2002-03-04 15:03               ` James Bottomley
2002-03-04 17:04                 ` Stephen C. Tweedie
2002-03-04 17:16                   ` Chris Mason
2002-03-04 18:05                     ` Stephen C. Tweedie
2002-03-04 18:28                       ` James Bottomley
2002-03-04 19:55                         ` Stephen C. Tweedie
2002-03-04 19:48                       ` Daniel Phillips
2002-03-04 19:57                         ` Stephen C. Tweedie
2002-03-04 21:06                           ` Daniel Phillips
2002-03-05 14:58                             ` Stephen C. Tweedie
2002-03-05  7:48                         ` Jens Axboe
2002-03-04 19:51                     ` Daniel Phillips
2002-03-05  7:42                       ` Jens Axboe
2002-03-04 17:35                   ` James Bottomley
2002-03-04 17:48                     ` Chris Mason
2002-03-04 18:11                       ` James Bottomley
2002-03-04 18:41                         ` Chris Mason
2002-03-04 21:34                         ` Stephen C. Tweedie
2002-03-04 18:09                     ` Stephen C. Tweedie
2002-03-04  8:19             ` Helge Hafting
2002-03-04 14:57             ` James Bottomley
2002-03-04 17:24               ` Chris Mason
2002-03-04 19:02                 ` Daniel Phillips
2002-03-05  7:22               ` Jeremy Higdon
2002-03-05 23:01                 ` Daniel Phillips
2002-03-04  4:21           ` Jeremy Higdon
2002-03-04  5:31             ` Daniel Phillips
2002-03-04  6:09               ` Jeremy Higdon
2002-03-04  7:57                 ` Daniel Phillips
2002-03-05  7:09                   ` Jeremy Higdon
2002-03-05 22:56                     ` Daniel Phillips
2002-03-04 16:52                 ` Stephen C. Tweedie
2002-03-04 18:15                   ` Daniel Phillips
2002-03-05  7:40                     ` Jens Axboe
2002-03-05 22:29                       ` Daniel Phillips
2002-03-12  7:01                         ` Jens Axboe
2002-03-10  5:24                   ` Douglas Gilbert
2002-03-11 11:13                     ` Kurt Garloff
2002-03-12  1:17                       ` GOTO Masanori
2002-03-12  6:58                       ` Jens Axboe
2002-03-13 22:37                         ` Peter Osterlund
2002-03-11 11:34                     ` Stephen C. Tweedie
2002-03-11 17:15                       ` James Bottomley
2002-03-04 14:48           ` James Bottomley
2002-03-06 13:59             ` Daniel Phillips
2002-03-06 14:34               ` James Bottomley
2002-02-25 10:57 ` Helge Hafting
2002-02-25 15:04   ` James Bottomley
  -- strict thread matches above, loose matches on Subject: below --
2002-03-01 15:26 Dieter Nützel
2002-03-01 16:00 ` James Bottomley
2002-02-21 23:30 Chris Mason
2002-02-22 14:19 ` Stephen C. Tweedie
2002-02-22 15:26   ` Chris Mason
2002-01-10  9:55 [ANNOUNCE] FUSE: Filesystem in Userspace 0.95 Miklos Szeredi
2002-01-13  3:10 ` Pavel Machek
2002-01-21 10:18   ` Miklos Szeredi
2002-01-23 10:47     ` Pavel Machek
2002-01-22 19:07 ` Daniel Phillips
2002-01-23  2:33   ` [Avfs] " Justin Mason
2002-01-23  5:26     ` Daniel Phillips

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