From: Con Kolivas <kernel@kolivas.org>
To: malc <av1474@comtv.ru>
Subject: Re: CPU load
Date: Mon, 12 Feb 2007 18:29:47 +1100
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On Monday 12 February 2007 18:10, malc wrote:
> On Mon, 12 Feb 2007, Con Kolivas wrote:
> > Lots of confusion comes from this, and often people think their pc
> > suddenly uses a lot less cpu when they change from 1000HZ to 100HZ and
> > use this as an argument/reason for changing to 100HZ when in fact the
> > massive _reported_ difference is simply worse accounting. Of course there
> > is more overhead going from 100 to 1000 but it doesn't suddenly make your
> > apps use 10 times more cpu.
>
> Yep. This, i belive, what made the mplayer developers incorrectly conclude
> that utilizing RTC suddenly made the code run slower, after all /proc/stat
> now claims that CPU load is higher, while in reality it stayed the same -
> it's the accuracy that has improved (somewhat)
>
> But back to the original question, does it look at what's running on timer
> interrupt only or any IRQ? (something which is more in line with my own
> observations)

During the timer interrupt only. However if you create any form of timer, they 
will of course have some periodicity relationship with the timer interrupt.

-- 
-ck
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