The /sys/block/bcache0/bcache/stats_total/bypassed should accumulate
(notice the stats_total), but stats_day only shows results with an
exponentially weighted average with a half life of 1 day.  If your
load varies during the day, the amount bypassed will swing up and down
accordingly.

Adam

On Thu, Jan 26, 2012 at 10:31 AM, David Rhodes Clymer
<[email protected]> wrote:
>
> Although the doc (Documentation/bcache.txt) seems to indicate that
> "bypassed" should contain cumulative IO for the stat period, I've
> noticed that it does not consistently increase. In fact, it increases
> and decreases quite a bit over a short period of time.
>
> root@zapazoid:~# date
> Thu Jan 26 13:23:34 EST 2012
> root@zapazoid:~# cat /sys/block/bcache0/bcache/stats_day/bypassed
> 5.4M
> root@zapazoid:~# cat /sys/block/bcache0/bcache/stats_day/bypassed
> 9.1M
> root@zapazoid:~# cat /sys/block/bcache0/bcache/stats_day/bypassed
> 1008k
> root@zapazoid:~# cat /sys/block/bcache0/bcache/stats_day/bypassed
> 2.4M
> root@zapazoid:~# cat /sys/block/bcache0/bcache/stats_day/bypassed
> 5.1M
> root@zapazoid:~# date
> Thu Jan 26 13:24:44 EST 2012
>
>
> This is while doing an rsync into a cached filesystem, which I would
> imagine would entail a significant amount of sequential writes.
>
> Am I just misunderstanding what this is supposed to be telling me?
>
> -davidc
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> the body of a message to [email protected]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
  • Stats David Rhodes Clymer
    • Re: Stats Adam Berkan

Reply via email to