From: axboe@fb.com (Jens Axboe)
Subject: [PATCH v2] NVMe: avoid kmalloc/kfree for smaller IO
Date: Thu, 29 Jan 2015 09:24:21 -0800 [thread overview]
Message-ID: <54CA6CC5.7090602@fb.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1501291714300.15481@localhost.lm.intel.com>
On 01/29/2015 09:21 AM, Keith Busch wrote:
> On Thu, 22 Jan 2015, Jens Axboe wrote:
>> Currently we allocate an nvme_iod for each IO, which holds the
>> sg list, prps, and other IO related info. Set a threshold of
>> 2 pages and/or 8KB of data, below which we can just embed this
>> in the per-command pdu in blk-mq. For any IO at or below
>> NVME_INT_PAGES and NVME_INT_BYTES, we save a kmalloc and kfree.
>>
>> For higher IOPS, this saves up to 1% of CPU time.
>
> Looks good to me, tests well on my machines. I had to make one minor
> modification to the diff for it to apply to your latest tree, but it's
> trivial and you'll see it (just below nvme_set_info()).
>
> Reviewed-by: Keith Busch <keith.busch at intel.com>
Thanks! I'll apply it for 3.20/drivers.
--
Jens Axboe
prev parent reply other threads:[~2015-01-29 17:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-22 19:07 [PATCH v2] NVMe: avoid kmalloc/kfree for smaller IO Jens Axboe
2015-01-29 17:21 ` Keith Busch
2015-01-29 17:24 ` Jens Axboe [this message]
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