From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: Flushing dirty data after bcache detach Date: Wed, 21 Aug 2013 23:07:01 -0700 Message-ID: <20130822060701.GC14935@kmo-pixel> References: <423285490.335846.1377074174264.JavaMail.root@thomas-krenn.com> <1057573722.337424.1377074937216.JavaMail.root@thomas-krenn.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <1057573722.337424.1377074937216.JavaMail.root-qD/LZSXtZz5FYGZjsVlUvw@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Georg =?utf-8?Q?Sch=C3=B6nberger?= Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org On Wed, Aug 21, 2013 at 10:48:57AM +0200, Georg Sch=C3=B6nberger wrote: > Hi bcache team, >=20 > we are currently developing performance test scripts with Fio for bca= che. > At the end of a test we want to detach and destroy the cache. Therefo= re we did: > echo 1 > /sys/block/$dev/bcache/detach > echo 1 > /sys/block/$dev/bcache/stop >=20 > echo 1 > /sys/fs/bcache/*/stop > echo 1 > /sys/fs/bcache/*/unregister >=20 > 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.