From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe - Profihost AG Subject: Re: can't get bache's sequential_cutoff to work Date: Thu, 25 Jul 2013 09:17:16 +0200 Message-ID: <51F0D0FC.4040002@profihost.ag> References: <51EE9056.7030903@profihost.ag> <51EEDC73.5020101@profihost.ag> <51EEE805.7090200@profihost.ag> <51EEE9D9.7090207@profihost.ag> <20130725001431.GA12364@kmo-pixel> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130725001431.GA12364@kmo-pixel> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Kent Overstreet Cc: Jack Wang , "linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-bcache@vger.kernel.org Am 25.07.2013 02:14, schrieb Kent Overstreet: > On Tue, Jul 23, 2013 at 10:38:49PM +0200, Stefan Priebe wrote: >> Mhm works directly on block device but not with XFS on top. > > That's odd... > > Do you suppose you could look at what blktrace says is going down? If > you could compare what blktrace says is going to the bcache device with > and without XFS, hopefully that'll show what's going wrong... > > Only thing I can think of that would cause it is for some reason XFS is > sending bios down in the wrong order... which normally wouldn't be _too_ > painful since both the elevator and the disk's cache will reorder the > IOs, so I can see how that would slip by. Hi, will try to have a look. But can it also be that the history of 128 entries is too small under my workload and bcache does not detect the sequence? Is there a way to try with a higher value like 1024? Stefan