From: Coly Li <colyli@suse.de>
To: Michael Lyle <mlyle@lyle.org>, tang.junhui@zte.com.cn
Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org
Subject: Re: [for-416 PATCH 3/3] bcache: allow quick writeback when backing idle
Date: Thu, 4 Jan 2018 00:54:28 +0800 [thread overview]
Message-ID: <42e6fd64-1ab3-3b4d-4dfe-70a76152d9d2@suse.de> (raw)
In-Reply-To: <0fdcfaaf-af7a-adb8-075d-b321b9df4ef7@lyle.org>
On 03/01/2018 12:23 AM, Michael Lyle wrote:
> On 01/02/2018 12:53 AM, tang.junhui@zte.com.cn wrote:
>> If no front-end I/O coming, would this cause write-back IOs one by one
>> (one write-back IO issued must after the completion of the previous IO)?
>> though with zero delay time, is the write-back performance still good?
>
Hi Mike,
> Yes-- this speeds up writeback during idle from 4k/sec to about 10MB/sec
> on my slow 5400RPM disk. (It writes back at about 20MB/sec with deep
> queues in the same scenario). So in this case it's about 2500x faster
> than current idle writeback, but half as fast as writeback with full
> device utilization.
>
Nice performance data!
> With only one I/O outstanding at a time, if front-end I/O starts latency
> for the first request is still good.
It is good idea, I like it.
Acked-by: Coly Li <colyli@suse.de>
Thanks for the effort :-)
Coly Li
next prev parent reply other threads:[~2018-01-03 16:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-02 8:53 [for-416 PATCH 3/3] bcache: allow quick writeback when backing idle tang.junhui
2018-01-02 16:23 ` Michael Lyle
2018-01-03 16:54 ` Coly Li [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-01-02 7:02 tang.junhui
2018-01-02 8:18 ` Michael Lyle
2017-12-28 0:47 [for-416 PATCH 1/3] bcache: writeback: collapse contiguous IO better Michael Lyle
2017-12-28 0:47 ` [for-416 PATCH 3/3] bcache: allow quick writeback when backing idle Michael Lyle
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