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From: John Garry <john.garry@huawei.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: <axboe@kernel.dk>, <linux-block@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <linux-scsi@vger.kernel.org>,
	<kashyap.desai@broadcom.com>, <chenxiang66@hisilicon.com>,
	<yama@redhat.com>, Douglas Gilbert <dgilbert@interlog.com>
Subject: Re: [PATCH] blk-mq: Use request queue-wide tags for tagset-wide sbitmap
Date: Tue, 11 May 2021 08:33:18 +0100	[thread overview]
Message-ID: <afa41d8d-d006-5c4f-d604-047ac737fd90@huawei.com> (raw)
In-Reply-To: <YJnVasOcaVU+4+Au@T590>

On 11/05/2021 01:52, Ming Lei wrote:
>> fixed.
>>
>> Ming and Yanhui report higher CPU usage and lower throughput in scenarios
>> where the fixed total driver tag depth is appreciably lower than the total
>> scheduler tag depth:
>> https://lore.kernel.org/linux-block/440dfcfc-1a2c-bd98-1161-cec4d78c6dfc@huawei.com/T/#mc0d6d4f95275a2743d1c8c3e4dc9ff6c9aa3a76b
>>
> No difference any more wrt. fio running on scsi_debug with this patch in
> Yanhui's test machine:
> 
> 	modprobe scsi_debug host_max_queue=128 submit_queues=32 virtual_gb=256 delay=1
> vs.
> 	modprobe scsi_debug max_queue=128 submit_queues=1 virtual_gb=256 delay=1
> 
> Without this patch, the latter's result is 30% higher than the former's.
> 

ok, good. I'll post a v2 with comments addressed.

> note: scsi_debug's queue depth needs to be updated to 128 for avoiding io hang,
> which is another scsi issue.
> 
I was just carrying Doug's patch to test.

Thanks,
John

      parent reply	other threads:[~2021-05-11  7:34 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-03 10:22 John Garry
2021-05-06  8:32 ` Ming Lei
2021-05-07 10:15   ` John Garry
2021-05-11  0:52 ` Ming Lei
2021-05-11  1:35   ` Douglas Gilbert
2021-05-11  1:47     ` Ming Lei
2021-05-11  7:33   ` John Garry [this message]

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