From: Shaohua Li <shli@kernel.org>
To: 刘正元 <liuzhengyuan@kylinos.com.cn>
Cc: linux-raid <linux-raid@vger.kernel.org>
Subject: Re: Poor written performance with RAID5 on ARM64
Date: Tue, 19 Apr 2016 06:59:17 -0700 [thread overview]
Message-ID: <20160419135917.GA2116@kernel.org> (raw)
In-Reply-To: <tencent_7B55CA2751E70C532CB35C8E@qq.com>
On Mon, Apr 18, 2016 at 01:43:04PM +0800, 刘正元 wrote:
> Hi,everyone. I upgrade kernel form 3.14.x to 4.4.x recently on my ARM64
> server. I create a RAID5 device with 8 disks on the server and have a dd
> test which like this "dd if=/dev/zero of=/dev/md5 bs=64K count=400000".
> Before upgrade it can reach 700M/s written and only 500M/s after upgrade.
> Then I disable the bitmap which means "mdadm create --bitmap=none", the speed
> can reach 800M/s with 4.4 kernel. I have a fast view on driver/md/bitmap.c
> and got no answer. I doubt X86 platform has the same question. So, what is
> the most difference between 3.14.x and 4.4.x about md driver. Where could I
> found the ChangeLog or commit about the driver. Any answer would be thankful.
did you observe any changes in iostat? Could you post blktrace from one of the
raid disk?
Thanks,
Shaohua
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next prev parent reply other threads:[~2016-04-19 13:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-18 5:43 Poor written performance with RAID5 on ARM64 刘正元
2016-04-19 13:59 ` Shaohua Li [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-04-20 4:16 刘正元
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