From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe - Profihost AG Subject: Re: bcache kernel 3.10 wrong bypassed values Date: Fri, 12 Jul 2013 08:13:36 +0200 Message-ID: <51DF9E90.8070408@profihost.ag> References: <51D52EA0.80302@profihost.ag> <20130712015559.GF17799@kmo-pixel> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130712015559.GF17799@kmo-pixel> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Kent Overstreet Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org Am 12.07.2013 03:55, schrieb Kent Overstreet: > On Thu, Jul 04, 2013 at 10:13:20AM +0200, Stefan Priebe - Profihost AG wrote: >> Hello list, >> >> while testing bcache i noticed that while writing a big 48GB file the >> sequential cutoff works fine i see only I/O on the disk but not on the >> cache. I thought i would afterwards see a bypassed value of around 48GB >> but it is only 1.2GB. >> >> Is this expected? Is bcache in kernel 3.10 stable for production usage? > > That sounds like a bug, but bcache in 3.10 certainly should be stable > for production usage. > > There can be some weirdness due to the way the stats work, there's a ~13 > second update interval (and also the intermediate counters are 32 bit > ints so if you manage to wrap that in 13 seconds you'll lose counts, but > it's counting sectors so I doubt that happened here). Mhm i doubt that too. But if i write 40GB shouldn't i see a bypass value near 40GB? It's just very small. > Does that sound like it might explain what you were seeing, or do you > think there's something else going on? No right no i don't believe that. Stefan