Also, please clarify that you are triggering a proxy with a priority of
29, and that your process are set to priority queue and priority float
(the priority of the process is not relevant).
From: > email@example.com > (Greg Laird) [mailto:> firstname.lastname@example.org> ]
Posted At: Tuesday, September 04, 2001 9:59 PM
Posted To: qnx4
Conversation: What runs at priority > 30?
Subject: Re: What runs at priority > 30?
I loose interrupts when I am only running my process (priority 29) and
photon and its drivers (priority 10). I actually miss interrupts at
16K when moving windows–not every time but often.
I am servicing an a/d converter that has a FIFO on it, so I can
probably work around this. I do use the values acquired to output
values to a d/a system and small timing errors now and then won’t be
too critical. I would just as soon solve the problem if it was not
Using sac does not contribute to my problems–I was loosing interrupts
and thought I would try sac to see if there was some activity with a
priority greater than my prio 29 service routine. That’s how I found
the priority 31. I assume that is my interrupt possibly not being
serviced due to the video chip hogging the buss.
On Tue, 4 Sep 2001 11:12:44 -0400, “Mario Charest”
email@example.com> > wrote:
“Greg Laird” <> firstname.lastname@example.org> > wrote in message
news:> email@example.com> …
This must be what is going on. Do you know how I might get around
Beware that when you move windowsaround you affect sac and possibly how
it averages numbers. What you might be seeing are normal interrupt
HD, serial port). Try running sac at higher priority.
For even better analysis, try getting Deja-View (a beta product)
Making sure your interrupt has the highest priority might help.
(-i option of Proc32)
Are there some video cards that don’t lock up the buss?
You have to look at embedded/real-time chip
for that, unfortunately I don’t have any specific info to give
you. Consumer video card are meant for consumer >
Do you have any idea how long a “long time” is?
No I don’t, from memory this was in the order of ms.
With all that being said, do you have a real problem keeping
up with 16K or are you worry about the output of sac only?
Thanks again for your help Mario. Best to you,
On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest”
firstname.lastname@example.org> > wrote:
Priority 31 are interrupts.
Many graphics card will hold the bus for a “long” time during
“Greg Laird” <> email@example.com> > wrote in message
news:> firstname.lastname@example.org> …
I am using qnx 4.25 (december 2000 cd). I have an application
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28.
have my interrupt servicing process running at priority 29 and
the flags word set to receive proxies in priority order.
The interrupt service routine does nothing more than clear the
interrupt bit in the devices register and then return with a proxy
start the interrupt service routine.
Using sin, it appears that my routine is the only process running
pri 29. Proc32 is 28 and there are other processes in the low
Now, all of this works fine until I start to move windows around
Photon. I should say that the photon processes (input, crt
photon, etc.) are all running at priority 10. I am running a dual
monitor system with 2 banchee drivers loaded.
I have started Photon’s sac utility and I notice that every once
while, a process with a priority greater than 30 runs when I am
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
I imagine that some process is starting up with a priority > 30,
interrupt routine is getting no cpu cycles and hence the problem.
What could be running? How do I stop it?
Thanks again for everyones help,