Re: [PATCH 4/4] nvme: add support for mq_ops->queue_rqs()

Jens Axboe
2021-12-06T16:33:42Z

On 12/6/21 12:40 AM, Christoph Hellwig wrote:
> On Fri, Dec 03, 2021 at 02:45:44PM -0700, Jens Axboe wrote:
>> This enables the block layer to send us a full plug list of requests
>> that need submitting. The block layer guarantees that they all belong
>> to the same queue, but we do have to check the hardware queue mapping
>> for each request.
>>
>> If errors are encountered, leave them in the passed in list. Then the
>> block layer will handle them individually.
>>
>> This is good for about a 4% improvement in peak performance, taking us
>> from 9.6M to 10M IOPS/core.
>
> This looks pretty similar to my proposed cleanups (which is nice), but
> back then you mentioned the cleaner version was much slower. Do you
> know what brought the speed back in this version?

Yes, it has that folded in and tweaked on top. Current version seems
to be fine.

--
Jens Axboe