Re: [PATCH v2] block: make iolatency avg_lat exponentially decay
From: Tejun Heo
Date: Wed Aug 01 2018 - 12:10:18 EST
On Wed, Aug 01, 2018 at 08:49:58AM -0700, Tejun Heo wrote:
> On Tue, Jul 31, 2018 at 05:25:59PM -0700, Dennis Zhou wrote:
> > + /*
> > + * CALC_LOAD takes in a number stored in fixed point representation.
> > + * Because we are using this for IO time in ns, the values stored
> > + * are significantly larger than the FIXED_1 denominator (2048).
> > + * Therefore, rounding errors in the calculation are negligible and
> > + * can be ignored.
> > + */
> > + exp_idx = min_t(int, BLKIOLATENCY_NR_EXP_FACTORS - 1,
> > + iolat->cur_win_nsec / BLKIOLATENCY_EXP_BUCKET_SIZE);
> Build bot is complaining about naked 64bit div. Should use one of the
> div64*() helpers.
> Looks good to me. Once Johannes's concerns are addressed, please feel
> free to add
Ooh, one nitpick. total_lat_avg is a bit of a misnomer now. Maybe
rename to lat_avg?