Jeffery,
I use the parallel port and set and clear a bit when I enter and exit a IRS
or thread (I use a different bit for each ISR or thread). Then I use an
o-scope to see what is happening. That way I have also documented my
embedded code to show the timing and how everything interacts.
Janet Estabridis
-----Original Message-----
From: David Olofson
To: Jeffrey Krasky; [EMAIL PROTECTED]
Sent: 2/15/01 7:55 AM
Subject: Re: real-time versus non-real-time
On Thursday 15 February 2001 15:40, Jeffrey Krasky wrote:
> > Hi,
> is there a way in Linux to run a process and determine which other
> processes might have been going on during the execution of your
process? I
> would like to run my task in real-time and see how long it takes to
run,
> and then run it in ordinary linux mode and see how long it takes to
run.
Well, if you want to be entirely sure you're not being disturbed, just
run
your thread as SCHED_FIFO at top prio - that will freeze the entire user
space until you release the CPU. (It's effective to the point that
you'll
have to press the reset button if your code doesn't feel like giving
up!)
> Then I want to note the differences, but I would like to also be able
to
> see, when running in ordinary linux mode, if anything else used any of
the
> same CPUs as my task did.
Not possible in SCHED_FIFO mode - the timesharing is entirely bypassed,
giving you full control over CPU utilization until you yield. However,
note
that the *kernel* still has higher priority than your thread, if it
should
feel like doing something.
Anyway, what are you looking for, really? There shouldn't be any
differences
in raw code execution speed, I think... (Unless you're going to compare
kernel vs user space ways of doing various kinds of I/O and that kind of
stuff, of course. :-)
//David
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.- David Olofson -------------------------------------------.
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