lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
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.)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists