From: David Sterba <dsterba@suse.cz>
To: Liu Bo <bo.li.liu@oracle.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v3] Btrfs: add readahead for send_write
Date: Wed, 5 Mar 2014 15:10:30 +0100 [thread overview]
Message-ID: <20140305141030.GI7004@suse.cz> (raw)
In-Reply-To: <1393985255-16974-1-git-send-email-bo.li.liu@oracle.com>
On Wed, Mar 05, 2014 at 10:07:35AM +0800, Liu Bo wrote:
> Btrfs send reads data from disk and then writes to a stream via pipe or
> a file via flush.
>
> Currently we're going to read each page a time, so every page results
> in a disk read, which is not friendly to disks, esp. HDD. Given that,
> the performance can be gained by adding readahead for those pages.
>
> Here is a quick test:
> $ btrfs subvolume create send
> $ xfs_io -f -c "pwrite 0 1G" send/foobar
> $ btrfs subvolume snap -r send ro
> $ time "btrfs send ro -f /dev/null"
>
> w/o w
> real 1m37.527s 0m9.097s
> user 0m0.122s 0m0.086s
> sys 0m53.191s 0m12.857s
>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
prev parent reply other threads:[~2014-03-05 14:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-05 2:07 [PATCH v3] Btrfs: add readahead for send_write Liu Bo
2014-03-05 14:10 ` David Sterba [this message]
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