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Subject: Re: [PATCH RFC] scsi: core: remove unsed 'restarts' from scsi_device
To:     Yu Kuai <yukuai1@huaweicloud.com>, Ming Lei <ming.lei@redhat.com>,
        Jan Kara <jack@suse.cz>
Cc:     jejb@linux.ibm.com, martin.petersen@oracle.com,
        linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        yi.zhang@huawei.com, "yukuai (C)" <yukuai3@huawei.com>
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From:   Yu Kuai <yukuai1@huaweicloud.com>
Message-ID: <8280fa32-4a96-be98-06ac-1890f95f026f@huaweicloud.com>
Date:   Tue, 29 Nov 2022 10:15:04 +0800
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Hi,

> Hi,
> 
> 在 2022/11/28 12:12, Ming Lei 写道:

>>
>> BTW, why do you drive nvme via megaraid instead nvme driver?
>>
>>> And by the way, after Jan's patch "blk-mq: Improve performance of non-mq
>>> IO schedulers with multiple HW queues", scsi_run_queue_async() can only
>>> garantee to run hw queue for the current cpu, not all the hw queues.
>>
>> That isn't true, each hctx is still run in case of none & kyber 
>> scheduler.

And I really suspect that why Jan's patch can improve performance is
because it avoid many run queues from scsi_run_queue_async().

> 
> Yes, but current default hctx shared elevator is deadline.
>>
>> thanks,
>> Ming
>>
>> .
>>
> 
> .
>