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Date: Fri, 27 Oct 2006 14:36:21 -0700 (PDT)
From: Indian Mogul <indian_mogul@yahoo.com>
Subject: Re: CPU Loading
To: Mike Galbraith <efault@gmx.de>, linux-kernel@vger.kernel.org
In-Reply-To: <1161933988.6102.28.camel@Homer.simpson.net>
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Thanks for the code snippet.. One more question. I
want to  load the cpu with x% load & take
measurements. For eg, cpu_burn <x> should load the CPU
 with x% occupancy.. Is there a way this could be
done? Any program / pointers greatly appreciated..

Thanks,
IM 

--- Mike Galbraith <efault@gmx.de> wrote:

> On Thu, 2006-10-26 at 22:37 -0700, Indian Mogul
> wrote:
> 
> > How can I load the CPU such that the scheduling
> time
> > slice is insuffucent for mplayer to playout the
> video?
> > To the mplayer the system thus appears "slow" ?
> 
> :) unusual request.
> 
> The proglet below, which someone posted a while
> back, should meet your
> needs nicely.  Fire up a few copies in the
> background with args like
> 5000 6000 7000 8000 9000.., and mplayer should
> become decidedly unhappy.
> 
> The scheduler round robin schedules tasks which it
> has classified as
> interactive (tasks which sleep somewhat regularly
> basically) at a higher
> rate than their timeslice to reduce latency, but the
> more tasks
> circulating at the same priority (or above) as
> mplayer, the bigger the
> latency hit mplayer will take.
> 
> 	-Mike
> 
> #include <stdlib.h>
> #include <unistd.h>
> 
> static void burn_cpu(unsigned int x)
> {
> 	static char buf[1024];
> 	int i;
> 	
> 	for (i=0; i < x; ++i)
> 		buf[i%sizeof(buf)] = (x-i)*3;
> }
> 
> int main(int argc, char **argv)
> {
> 	unsigned long burn;
> 	if (argc != 2)
> 		return 1;
> 	burn = (unsigned long)atoi(argv[1]);
> 	while(1) {
> 		burn_cpu(burn*1000);
> 		usleep(1);
> 	}
> 	return 0;
> }
>


> 
> 




 
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