Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

[Florian Schmidt <mista.tapas@gmx.net>]

On Sat, 30 Oct 2004 15:52:04 -0400
Lee Revell <rlrevell@joe-job.com> wrote:

> Yup there is definitely something not right:

[snip]

> You should modify the program to print something when it sees a big
> miss.  This would make it easier to figure out what kind of system
> activity triggers the problem.

right, i just wanted to avoid doing that from the process that polls itself,
because a std::cout << "ugh!" << std::endl; might already be enough to skew
the following irq's, right?

anyways, this new version [just upped] prints a line when a missed irq was
detected. Also this version understands a third parameter which acts as an
upper threshold. A line is printed when the difference of the cycle count of
two consecutive wakeups is greater than the threshold.

run it once w/o threshold on an idle system to see what a useful thresh
would be.

i use it like this for example:

./rt_wakeup 1024 50000 1200000

What's the best way to find out the cycles/s of the cpu? This way the
input/output could become a little nicer [because then i can calculate
programatically how long a "perfect" period should be in cycles].

flo