Hi Bob!

Antwort auf eine Message von Bob Liles an Michael Douglass:

 MD>> Ok, even when I do sense OS/2, how can I make my program release time
 MD>> slices while sitting in an input loop?
Should be avoided if possible. Rather use interrupt- or event-driven techniques.
 MD>> I have a loop that checks for keyboard and mouse input, I would
like to allow the release of
 MD>> OS/2 time slices for OS/2 users.

 BL> I don't know anything about C or C++ programming, but in assembly you
 BL> do that by pushing a double word "0" onto the stack and doing a far
 BL> call to DosSleep.  
AFAIK there is/was a little bug (?). DosSleep (0L) won't release a complete
timeslice, but DosSleep (1L) will. I'm not very sure about this, but after
a few tests, I got very different results from those two calls. You'll have
to try, which one fits better for the input loop.

I've used this for some measuring purposes, actually I tried to gather
knowledge about OS/2s thread switching. Although my results are not very
exact, I think the thread switching time is below 60 micro seconds on a
486/66.
When measuring 64 Threads usind DosSleep(1L), the CPU load raises to 17%.
When doing the same with DosSleep(0L) to "pre-empt" the current
thread voluntarily, the CPU load raises to 100%.
Has anyone suggestions on how to measure this thread or process switching
time more exactly ?
       __
       |_)      Internet: Haller{at}ti-nov1.fbe.fh-weingarten.de
cu/2.1 |atrick  Fidonet:  2:246/2320.18 ZebraNet: 7:7000/7998

--- FleetStreet 0.88wb