Hi Peter,
On Wed, Mar 29, 2017 at 12:41:26PM +0200, Peter Zijlstra wrote:
> On Wed, Mar 29, 2017 at 08:04:42AM +0800, Yuyang Du wrote:
> > Yes, you need to, and let me do it too and learn how you will rewrite
> > it.
>
> I've meanwhile written this. Does that work for you?
It works. You sort it out.
I hope I get along with going into detail too ...
Some grammar and typo issues:
> ---
> Subject: sched/fair: Optimize ___update_sched_avg()
> From: Yuyang Du <yuyang...@intel.com>
> Date: Mon, 13 Feb 2017 05:44:23 +0800
>
> The main PELT function ___update_load_avg(), that implements the
~~~~
which
> accumulation and progression of the geometric average series, is
> implemented along the following lines for the scenario where the time
> delta spans all 3 possible sections (see figure below):
>
> 1. add the remainder of the last incomplete period
> 2. decay old sum
> 3. accumulate new sum in full periods since last_update_time
> 4. accumulate the current incomplete period
> 5. update averages
>
> Or:
>
> d1 d2 d3
> ^ ^ ^
> | | |
> |<->|<----------------->|<--->|
> ... |---x---|------| ... |------|-----x (now)
>
>
> load_sum' = (load_sum + weight * scale * d1) * y^(p+1) + (1,2)
>
> p
> weight * scale * 1024 * \Sum y^n + (3)
> n=1
>
> weight * sclae * d3 * y^0 (4)
~~~~~
scale
Thanks,
Yuyang
