From: Randy Dunlap <rdunlap@infradead.org>
To: "Javier Gonzalez" <javier@cnexlabs.com>,
"Matias Bjørling" <m@bjorling.me>
Cc: Jens Axboe <axboe@fb.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Hans Holmberg (C)" <hans.holmberg@cnexlabs.com>
Subject: Re: [GIT PULL 18/25] lightnvm: set target over-provision on create ioctl
Date: Fri, 5 Jan 2018 12:17:23 -0800 [thread overview]
Message-ID: <2d6747af-8287-e9e7-60a7-3047811ce45e@infradead.org> (raw)
In-Reply-To: <A85FDAC1-5A0C-4F09-AB6D-B08A388A918B@cnexlabs.com>
On 01/05/2018 11:56 AM, Javier Gonzalez wrote:
>> On 5 Jan 2018, at 20.53, Matias Bjørling <m@bjorling.me> wrote:
>>
>> On 01/05/2018 08:52 PM, Javier Gonzalez wrote:
>>>> On 5 Jan 2018, at 20.33, Randy Dunlap <rdunlap@infradead.org> wrote:
>>>>
>>>> On 01/05/2018 05:16 AM, Matias Bjørling wrote:
>>>>> From: Javier González <javier@cnexlabs.com>
>>>>>
>>>>> Allow to set the over-provision percentage on target creation. In case
>>>>> that the value is not provided, fall back to the default value set by
>>>>> the target.
>>>>>
>>>>> In pblk, set the default OP to 11% of the total size of the device
>>>>
>>>>> +#define PBLK_DEFAULT_OP (11)
>>>>
>>>> Hi,
>>>> Just curious -- where does 11 come from? Is it a spec value?
>>> 11 stands for 11% over-provisioning for the media to allow garbage
>>> collection. Different SSDs have different values based on the targeted
>>> workload - 11% is a common default value for standard drives.
>>> The spec. does not specify any default values of over-provisioning.
>>> Javier.
>>
>> I think what Randy means is, why is the value not 20% or 7%, which is the traditional over-provisioning on SSDs.
>
> We decided 11% based on customer input, but 7% and 20% are also good
> default values. I'm ok with having any of those as default - anyone
> caring about OP will define the value on target creation, which is the
> primary objective of this patch.
Got it. Thanks.
--
~Randy
next prev parent reply other threads:[~2018-01-05 20:17 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-05 13:15 [GIT PULL 00/25] LightNVM updates for 4.16 Matias Bjørling
2018-01-05 13:15 ` [GIT PULL 01/25] null_blk: remove lightnvm support Matias Bjørling
2018-01-05 13:15 ` [GIT PULL 02/25] lightnvm: remove rrpc Matias Bjørling
2018-01-05 13:15 ` [GIT PULL 03/25] lightnvm: use internal pblk methods Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 04/25] lightnvm: remove hybrid ocssd 1.2 support Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 05/25] lightnvm: remove unnecessary field from nvm_rq Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 06/25] lightnvm: remove lower page tables Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 07/25] lightnvm: make geometry structures 2.0 ready Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 08/25] lightnvm: refactor target type lookup Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 09/25] lightnvm: guarantee target unique name across devs Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 10/25] lightnvm: pblk: compress and reorder helper functions Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 11/25] lightnvm: pblk: remove pblk_for_each_lun helper Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 12/25] lightnvm: pblk: refactor emeta consistency check Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 13/25] lightnvm: pblk: rename sync_point to flush_point Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 14/25] lightnvm: pblk: clear flush point on completed writes Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 15/25] lightnvm: pblk: prevent premature sync point resets Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 16/25] lightnvm: pblk: remove pblk_gc_stop Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 17/25] lightnvm: pblk: use exact free block counter in RL Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 18/25] lightnvm: set target over-provision on create ioctl Matias Bjørling
2018-01-05 19:33 ` Randy Dunlap
2018-01-05 19:52 ` Javier Gonzalez
2018-01-05 19:53 ` Matias Bjørling
2018-01-05 19:56 ` Javier Gonzalez
2018-01-05 20:17 ` Randy Dunlap [this message]
2018-01-05 13:16 ` [GIT PULL 19/25] lightnvm: pblk: ignore high ecc errors on recovery Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 20/25] lightnvm: pblk: do not log recovery read errors Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 21/25] lightnvm: pblk: ensure kthread alloc. before kicking it Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 22/25] lightnvm: pblk: free write buffer on init failure Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 23/25] lightnvm: pblk: print instance name on instance info Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 24/25] lightnvm: pblk: add iostat support Matias Bjørling
2018-01-05 15:42 ` Jens Axboe
2018-01-05 18:33 ` Matias Bjørling
2018-01-08 11:54 ` Christoph Hellwig
2018-01-08 12:53 ` Javier González
2018-01-08 13:31 ` Matias Bjørling
2018-01-05 13:16 ` [GIT PULL 25/25] lightnvm: pblk: refactor pblk_ppa_comp function Matias Bjørling
2018-01-05 15:50 ` [GIT PULL 00/25] LightNVM updates for 4.16 Jens Axboe
2018-01-05 18:34 ` Matias Bjørling
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