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From: Tejun Heo <tj@kernel.org>
To: Weiping Zhang <zwp10758@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, cgroups@vger.kernel.org
Subject: Re: [RFC 0/3] blkcg: add blk-iotrack
Date: Thu, 26 Mar 2020 12:14:41 -0400
Message-ID: <20200326161328.GN162390@mtj.duckdns.org> (raw)
In-Reply-To: <CAA70yB4e65nbV=ZA8OT-SUkq+ZQOGGB9e-3QKJ_PqXjVaXGvFA@mail.gmail.com>

On Thu, Mar 26, 2020 at 11:08:45PM +0800, Weiping Zhang wrote:
> But iocost_test1 cannot get 8/(8+1) iops,  and the total disk iops
> is 737559 < 79388, even I change rrandiops=637000.

iocost needs QoS targets set especially for deep queue devcies. W/o QoS targets,
it only throttles when QD is saturated, which might not happen at all depending
on fio job params.

Can you try with sth like the following in io.cost.qos?

  259:0 enable=1 ctrl=user rpct=95.00 rlat=5000 wpct=50.00 wlat=10000

In case you see significant bw loss, step up the r/wlat params.

Thanks.

-- 
tejun

  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-21  1:20 Weiping Zhang
2020-03-21  1:21 ` [RFC 1/3] update the real issue size when bio_split Weiping Zhang
2020-03-21  1:21 ` [RFC 2/3] bio: track timestamp of submitting bio the disk driver Weiping Zhang
2020-03-21  1:21 ` [RFC 3/3] blkcg: add blk-iotrack Weiping Zhang
2020-03-24 18:27 ` [RFC 0/3] " Tejun Heo
2020-03-25 12:49   ` Weiping Zhang
2020-03-25 14:12     ` Tejun Heo
2020-03-25 16:45       ` Weiping Zhang
2020-03-26 15:08         ` Weiping Zhang
2020-03-26 16:14           ` Tejun Heo [this message]
2020-03-26 16:27             ` Weiping Zhang
2020-03-31 14:19               ` Tejun Heo
2020-03-27  6:27 ` [RFC PATCH v2 " Weiping Zhang

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