On 11/17/21 8:55 AM, Jens Axboe wrote:
> On 11/17/21 1:39 AM, Christoph Hellwig wrote:
>> On Tue, Nov 16, 2021 at 08:38:07PM -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.
>>
>> The concept looks sensible, but the loop in nvme_queue_rqs is a complete
>> mess to follow. What about something like this (untested) on top?
>
> Let me take a closer look.
Something changed, efficiency is way down:
2.26% +4.34% [nvme] [k] nvme_queue_rqs
--
Jens Axboe
