linux-kernel - The 10ms averager in fair.c

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Message-id: <op.wlf5j0i76426ze@localhost.localdomain>
Date:	Sun, 30 Sep 2012 13:44:14 +0200
From:	Uwaysi Bin Kareem <uwaysi.bin.kareem@...adoxuncreated.com>
To:	linux-kernel@...r.kernel.org
Subject: The 10ms averager in fair.c

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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