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SubjectRe: The 10ms averager in fair.c
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Just to illustrate, you have a filter that lasts 10ms, and a cpu process  
that lasts 100uS

Original spike

5 |
4 |
3 |
2 |
1 |
0 |
0ms_______________________10ms
Filtered spike

5
4
3
2
1 .....................
0.. ..
0ms________________________10ms

Not only is the filtered spike, much lower, but it lasts long beyond the
100uS spike. (10ms). Why would that be used in something that should
represent cpu-usage?

Peace Be With You.


On Sun, 30 Sep 2012 13:44:14 +0200, Uwaysi Bin Kareem
<uwaysi.bin.kareem@paradoxuncreated.com> wrote:

> Hiya. I just had an initial look at fair.c
>
> There seems to be a 10ms averager in there?
>
> You are aware that that means you work on delayed values?
>
> Isn`t that counterintuitive to the principle of sharing?
>
> That means short bursts of cpu-use will be filtered out, and given less
> cpu time.
> Starting applications won`t have their cpu-usage before 5ms, which is
> quite a bit on modern machines. Well if you use a linearphase filter, I
> don`t know what kind of averager you use. The best would ofcourse be to
> use a minimalphase gaussian averager. Which might be overkill. Atleast a
> one-pole iir, buf = buf + (-buf + in) * cut)); One pole IIRs also have a
> better frequency response.
>
> When you are working with low-latencies, wouldn`t it be better if such
> things are tuned for target latency. I think few care about latency
> after 0.2ms. So say the filter should be set to 0.4ms max.
>
> Why would you want to filter cpu-usage also really?
>
> Peace Be With You.
>
> (please CC me.)


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