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From: Yu Kuai <yukuai1@huaweicloud.com>
To: "Holger Hoffstätte" <holger@applied-asynchrony.com>,
	linux-block <linux-block@vger.kernel.org>,
	"Yu Kuai" <yukuai1@huaweicloud.com>,
	"yukuai (C)" <yukuai3@huawei.com>,
	"zhangyi (F)" <yi.zhang@huawei.com>
Subject: Re: wbt_lat_usec still set despite wbt disabled by BFQ
Date: Tue, 13 Sep 2022 21:39:06 +0800	[thread overview]
Message-ID: <17e0e889-e848-0bd3-3203-cb4e9b801462@huaweicloud.com> (raw)
In-Reply-To: <a5041479-f417-2b95-b645-56e665a7e557@applied-asynchrony.com>

Hi, Holger

在 2022/08/18 1:12, Holger Hoffstätte 写道:
> 
> I just noticed that my device configured with BFQ still shows wbt_lat_usec
> as configured, despite the fact that BFQ disables WBT in bfq_init_queue 
> [1]:
> 
> $cat /sys/block/sdc/queue/scheduler
> mq-deadline [bfq] none
> $cat /sys/block/sdc/queue/wbt_lat_usec
> 75000
> 
> Is this supposed to be 0 (since it's disabled) or is sysfs confused?
> 
> Thanks,
> Holger

I'm reviewing wbt codes recently, and I found that this problem will
happen if the default elevator is bfq. I'll try to fix this, do you mind
if I add reported-by tag?

Thanks,
Kuai
> 
> [1] 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/block/bfq-iosched.c#n7195 
> 
> 
> .
> 


  reply	other threads:[~2022-09-13 13:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-17 17:12 wbt_lat_usec still set despite wbt disabled by BFQ Holger Hoffstätte
2022-09-13 13:39 ` Yu Kuai [this message]
2022-09-13 14:12   ` Holger Hoffstätte
2022-09-13 14:20     ` Yu Kuai
2022-09-13 16:13       ` Holger Hoffstätte
2022-09-14  1:35         ` Yu Kuai
2022-09-14  6:05           ` Holger Hoffstätte
2022-09-14  9:23             ` Yu Kuai

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