From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Chris Samuel <chris@csamuel.org>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: discard synchronous on most SSDs?
Date: Sun, 16 Mar 2014 12:22:05 -0400 [thread overview]
Message-ID: <yq1a9cqw1ua.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <4448214.x9oPWjPhdL@quad> (Chris Samuel's message of "Sat, 15 Mar 2014 16:25:05 +1100")
>>>>> "Chris" == Chris Samuel <chris@csamuel.org> writes:
Chris> It looks like drives that do support it can be detected with the
Chris> kernel helper function ata_fpdma_dsm_supported() defined in
Chris> include/linux/libata.h.
Chris> I wonder if it would be possible to use that knowledge to extend
Chris> the smartctl's --identify functionality to report this?
Queued trim support is indicated in a log page and not the identify
information. However, we can get to the information we want using
smartctl's ability to look at log pages.
I don't have a single drive from any vendor in the lab that supports
queued trim, not even a prototype. I went out and bought a 840 EVO this
morning because the general lazyweb opinion seemed to indicate that this
drive supports queued trim. Well, it doesn't. At least not in the 120GB
version:
# smartctl -l gplog,0x13 /dev/sda
smartctl 5.43 2012-06-30 r3573 [x86_64-linux-3.14.0-rc6+] (local build)
Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net
General Purpose Log 0x13 does not exist (override with '-T permissive' option)
If there's a drive with a working queued trim implementation out there,
I'd like to know about it...
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2014-03-16 16:22 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-09 7:48 Massive BTRFS performance degradation KC
2014-03-09 8:17 ` Swâmi Petaramesh
2014-03-09 10:01 ` Martin Steigerwald
2014-03-09 10:23 ` Swâmi Petaramesh
2014-03-09 11:33 ` Hugo Mills
2014-03-09 11:54 ` Martin Steigerwald
2014-03-09 12:10 ` Swâmi Petaramesh
2014-03-09 17:14 ` boris
2014-03-14 2:11 ` discard synchronous on most SSDs? Marc MERLIN
2014-03-14 3:39 ` Chris Murphy
2014-03-14 5:17 ` Marc MERLIN
2014-03-14 7:33 ` Chris Samuel
2014-03-14 19:26 ` Marc MERLIN
2014-03-14 19:57 ` Martin K. Petersen
2014-03-14 20:46 ` Holger Hoffstätte
2014-03-15 4:21 ` Marc MERLIN
2014-03-15 9:38 ` Holger Hoffstätte
2014-03-15 5:25 ` Chris Samuel
2014-03-15 6:48 ` Chris Samuel
2014-03-15 11:26 ` Duncan
2014-03-15 22:48 ` Chris Samuel
2014-03-16 6:06 ` Marc MERLIN
2014-03-16 17:09 ` Chris Murphy
2014-03-16 16:22 ` Martin K. Petersen [this message]
2014-03-16 17:50 ` Marc MERLIN
2014-03-15 4:06 ` Chris Samuel
2014-03-16 16:07 ` Martin K. Petersen
2014-03-14 12:07 ` Duncan
2014-03-14 21:44 ` Chris Murphy
2014-03-14 7:27 ` Chris Samuel
2014-03-09 17:36 ` Massive BTRFS performance degradation Austin S Hemmelgarn
2014-03-09 18:55 ` Tobias Holst
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