From mboxrd@z Thu Jan 1 00:00:00 1970 From: Georg =?utf-8?Q?Sch=C3=B6nberger?= Subject: Flushing dirty data after bcache detach Date: Wed, 21 Aug 2013 10:48:57 +0200 (CEST) Message-ID: <1057573722.337424.1377074937216.JavaMail.root@thomas-krenn.com> References: <423285490.335846.1377074174264.JavaMail.root@thomas-krenn.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <423285490.335846.1377074174264.JavaMail.root-qD/LZSXtZz5FYGZjsVlUvw@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org Hi bcache team, we are currently developing performance test scripts with Fio for bcach= e. 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 ca= che. After detaching the dirty data flush rate was about 900KB/s from S= SD to HDD. Is there a way to accelerate flushing of dirty data? What is the correct way to detach/destroy a writeback caching device? * Kernel: 3.11.0-2-generic #5-Ubuntu SMP Mon Aug 12 16:09:51 UTC 2013 = x86_64 x86_64 x86_64 GNU/Linux * Kernel module info: filename: /lib/modules/3.11.0-2-generic/kernel/drivers/md/bcache/= bcache.ko author: Kent Overstreet license: GPL license: GPL author: Kent Overstreet srcversion: EE441BF41AAB31C3E44F5D2 depends: =20 intree: Y vermagic: 3.11.0-2-generic SMP mod_unload modversions=20 * iostat while flushing after detach: Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn sda 0.00 0.00 0.00 0 0 sdc 229.50 912.00 6.00 1824 12 sdb 228.00 0.00 912.00 0 1824 bcache0 0.00 0.00 0.00 0 0 Thanks a lot for your help in advance, Georg. -- : Georg Sch=C3=B6nberger : Research & Development Executive : Thomas-Krenn.AG | The server-experts : http://www.thomas-krenn.com | http://www.thomas-krenn.com/wiki