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Date: Sat, 14 Apr 2007 14:02:20 +0200
From: Ingo Molnar <mingo@elte.hu>
To: surya.prabhakar@wipro.com
Cc: kernel@kolivas.org, linux-kernel@vger.kernel.org,
       torvalds@linux-foundation.org, akpm@linux-foundation.org,
       npiggin@suse.de, efault@gmx.de, arjan@infradead.org, tglx@linutronix.de,
       wli@holomorphy.com
Subject: Re: [TEST RESULT]massive_intr.c -- cfs/vanilla/sd-0.40
Message-ID: <20070414120220.GA2346@elte.hu>
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* surya.prabhakar@wipro.com <surya.prabhakar@wipro.com> wrote:

> Hi Ingo,
>   Did a test with massive_intr.c on a standard linux desktop.
> for vanilla, con's Sd-0.40 and cfs.

thanks!

> [surya@bluegenie tests]$ ./massive_intr 10 10
> 002435  00000120
> 002439  00000120
> 002441  00000120
> 002434  00000120
> 002436  00000120
> 002440  00000120
> 002432  00000120
> 002437  00000120
> 002433  00000120
> 002438  00000120
> 
> Felt it is too much fair, will try another pass ;)

hehe :)

> [surya@bluegenie tests]$ ./massive_intr 10 10
> 002961  00000121
> 002965  00000120
> 002964  00000121
> 002959  00000120
> 002956  00000121
> 002963  00000121
> 002960  00000121
> 002962  00000121
> 002958  00000122
> 002957  00000122

btw., other schedulers might work better with some more test-time: i'd 
suggest to use 60 seconds (./massive_intr 10 60) [or maybe more, using 
more threads] to see long-term fairness effects.

> [...] Will be trying out ringtest in the next round.

cool. ringtest.c is intended to be used the following way: start it, it 
will generate a 99% busy system (but it is using a ring of 100 tasks, 
where each tasks runs for 100 msecs then sleeps for 1 msec, so every 
task gets a turn every 10 seconds). If you add a pure CPU hog to the 
system, for example an infinite shell loop:

	while :; do :; done &

then a 'fair' scheduler would give roughly 50% of CPU time to the CPU 
hog (and the ringtest.c tasks take up the other 50%).

	Ingo