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From: Kent Overstreet <kmo-PEzghdH756F8UrSeD/g0lQ@public.gmane.org>
To: "Georg Schönberger"
	<gschoenberger-qD/LZSXtZz5FYGZjsVlUvw@public.gmane.org>
Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: Flushing dirty data after bcache detach
Date: Wed, 21 Aug 2013 23:07:01 -0700	[thread overview]
Message-ID: <20130822060701.GC14935@kmo-pixel> (raw)
In-Reply-To: <1057573722.337424.1377074937216.JavaMail.root-qD/LZSXtZz5FYGZjsVlUvw@public.gmane.org>

On Wed, Aug 21, 2013 at 10:48:57AM +0200, Georg Schönberger wrote:
> Hi bcache team,
> 
> we are currently developing performance test scripts with Fio for bcache.
> At the end of a test we want to detach and destroy the cache. Therefore we did:
>     echo 1 > /sys/block/$dev/bcache/detach
>     echo 1 > /sys/block/$dev/bcache/stop
> 
>     echo 1 > /sys/fs/bcache/*/stop
>     echo 1 > /sys/fs/bcache/*/unregister
> 
> With a simple randwrite test with we had about 2GB dirty data in the cache. After detaching the dirty data flush rate was about 900KB/s from SSD to HDD.
> Is there a way to accelerate flushing of dirty data?
> What is the correct way to detach/destroy a writeback caching device?

The stop is unnecessary for the cache set (that'll shut down the cache
set without detaching anything or flushing dirty data).

900KB/sec sounds like a bug though - I'll try and take a look at it
tomorrow.

      parent reply	other threads:[~2013-08-22  6:07 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <423285490.335846.1377074174264.JavaMail.root@thomas-krenn.com>
     [not found] ` <423285490.335846.1377074174264.JavaMail.root-qD/LZSXtZz5FYGZjsVlUvw@public.gmane.org>
2013-08-21  8:48   ` Flushing dirty data after bcache detach Georg Schönberger
     [not found]     ` <1057573722.337424.1377074937216.JavaMail.root-qD/LZSXtZz5FYGZjsVlUvw@public.gmane.org>
2013-08-22  6:07       ` Kent Overstreet [this message]

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