Re: bcache kernel 3.10 wrong bypassed values

[Stefan Priebe - Profihost AG <s.priebe-2Lf/h1ldwEHR5kwTpVNS9A@public.gmane.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