Re: [BUG]Writeback Cgroup/Dirty Throttle: very small buffered write thoughput caused by writeback cgroup and dirty thottle

From	Tejun Heo <tj@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [BUG]Writeback Cgroup/Dirty Throttle: very small buffered write thoughput caused by writeback cgroup and dirty thottle
Date	2016-05-27 20:30 +0200
Message-ID	<rDuGe-6SR-15@gated-at.bofh.it> (permalink)
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Hello,

Sorry about the delay.  I forgot about this thread.

On Fri, May 13, 2016 at 02:11:53PM +0800, Miao Xie wrote:
> Better than the kernel without patch. Now the benchmark could reach
> the device bandwidth after 5-8 seconds.  But at the beginning, it
> was still very slow, and its thoughput was only 4MB/s for ~4
> seconds, then it could go up in 1~3 seconds.

I see.  As this fix is needed anyways, I'll send it up.  As for the
ramp-up, it could be normal.  There are estimators which take running
avg and modulate the threshold accordingly and the starting values are
conservative, so a short ramp-up time can be coming from that.

Thanks.

-- 
tejun

Thread

Re: [BUG]Writeback Cgroup/Dirty Throttle: very small buffered write  thoughput caused by writeback cgroup and dirty thottle Tejun Heo <tj@kernel.org> - 2016-05-12 20:10 +0200
  Re: [BUG]Writeback Cgroup/Dirty Throttle: very small buffered write  thoughput caused by writeback cgroup and dirty thottle Miao Xie <miaoxie@huawei.com> - 2016-05-13 08:20 +0200
    Re: [BUG]Writeback Cgroup/Dirty Throttle: very small buffered write  thoughput caused by writeback cgroup and dirty thottle Tejun Heo <tj@kernel.org> - 2016-05-27 20:30 +0200
  [PATCH block/for-4.7-fixes] writeback: use higher precision  calculation in domain_dirty_limits() Tejun Heo <tj@kernel.org> - 2016-05-27 20:40 +0200
    Re: [PATCH block/for-4.7-fixes] writeback: use higher precision  calculation in domain_dirty_limits() Jan Kara <jack@suse.cz> - 2016-05-30 10:10 +0200
    Re: [PATCH block/for-4.7-fixes] writeback: use higher precision  calculation in domain_dirty_limits() Jens Axboe <axboe@kernel.dk> - 2016-05-30 17:00 +0200

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