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Date: Wed, 18 Dec 2013 11:09:44 +0000
From: Leonidas Spyropoulos <artafinde@gmail.com>
To: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] Btrfs: improve the performance fluctuating of the fsync
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On Wed, Dec 18, 2013 at 06:52:44PM +0800, Miao Xie wrote:
> In order to improve the performance of fsync, we use the outstanding
> ordered extents to avoid looking up the checksum from the csum tree.
> But we didn't filter out the ordered extents whose csum is still being
> calculated, when we got those ordered extents, we had to wait for the
> csum calculation. It made the performance dropped down suddenly. (On
> my box, it drop down from 56MB/s to 4-10MB/s)
> 
> But actually, the csum calculation of the ordered extents which were
> introduced by the current fsync had already completed. Those ordered
> extents whose csum was being calculated didn't belong to the current
> fsync, we can ignore them.
> 
> By this patch, the performance fluctuating doesn't happen, and the average
> performance grows up by ~2%.
> [..] 

Will this help with apt-get performance over btrfs file system? As far as I understand it it's happening because of multiple fsync calls.