What runs at priority > 30?

QNX Newsgroups (Archives) qdn.public.qnx4
1

Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28. I
have my interrupt servicing process running at priority 29 and have
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 to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running at
pri 29. Proc32 is 28 and there are other processes in the low 20’s.

Now, all of this works fine until I start to move windows around with
Photon. I should say that the photon processes (input, crt drivers,
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 in a
while, a process with a priority greater than 30 runs when I am moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30, so my
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,
Greg Laird

2

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

“Greg Laird” <glaird@pacifier.com> wrote in message
news:3b941279.77606@inn.qnx.com…

Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28. I
have my interrupt servicing process running at priority 29 and have
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 to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running at
pri 29. Proc32 is 28 and there are other processes in the low 20’s.

Now, all of this works fine until I start to move windows around with
Photon. I should say that the photon processes (input, crt drivers,
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 in a
while, a process with a priority greater than 30 runs when I am moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30, so my
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,
Greg Laird

3

This must be what is going on. Do you know how I might get around
this? Are there some video cards that don’t lock up the buss? Do you
have any idea how long a “long time” is?

Thanks again for your help Mario. Best to you,
Greg Laird



On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest”
<mcharest@zinformatic.com> wrote:

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

“Greg Laird” <> glaird@pacifier.com> > wrote in message
news:> 3b941279.77606@inn.qnx.com> …
Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28. I
have my interrupt servicing process running at priority 29 and have
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 to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running at
pri 29. Proc32 is 28 and there are other processes in the low 20’s.

Now, all of this works fine until I start to move windows around with
Photon. I should say that the photon processes (input, crt drivers,
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 in a
while, a process with a priority greater than 30 runs when I am moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30, so my
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,
Greg Laird

4

“Greg Laird” <glaird@teleport.com> wrote in message
news:3b94e6ee.3176587@inn.qnx.com…

This must be what is going on. Do you know how I might get around
this?

Beware that when you move windowsaround you affect sac and possibly how
it averages numbers. What you might be seeing are normal interrupt
(network,
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 :wink:

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,
Greg Laird



On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest”
mcharest@zinformatic.com> > wrote:

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

“Greg Laird” <> glaird@pacifier.com> > wrote in message
news:> 3b941279.77606@inn.qnx.com> …
Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28. I
have my interrupt servicing process running at priority 29 and have
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 to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running at
pri 29. Proc32 is 28 and there are other processes in the low 20’s.

Now, all of this works fine until I start to move windows around with
Photon. I should say that the photon processes (input, crt drivers,
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 in a
while, a process with a priority greater than 30 runs when I am moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30, so my
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,
Greg Laird
\

5

Mario Charest <mcharest@zinformatic.com> wrote:

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

Usually if they do, it is a graphics driver bug. There was a bug
in the Banshee driver at one point, where it was not polling its
FIFO correctly, and writes to the draw engine registers were
blocking (the adapter would put wait states onto the bus).

I’m not sure if the fix has made into QNX4 yet; make sure you have
the latest patch. Also, it might be worth trying a different
video card, just to narrow things down.

Dave

“Greg Laird” <> glaird@pacifier.com> > wrote in message
news:> 3b941279.77606@inn.qnx.com> …
Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28. I
have my interrupt servicing process running at priority 29 and have
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 to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running at
pri 29. Proc32 is 28 and there are other processes in the low 20’s.

Now, all of this works fine until I start to move windows around with
Photon. I should say that the photon processes (input, crt drivers,
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 in a
while, a process with a priority greater than 30 runs when I am moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30, so my
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,
Greg Laird

6

On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest” <mcharest@zinformatic.com> wrote:

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

Do the graphics cards use an IRQ?
Most times I’ve looked show_pci or similar shows IRQ as not connected for the VGA?

7

As far as I know, the banchee cards do not use interrupts. I am using
two banchee cards in my system and show_pci indicates that they are
configred to use interrupt 11. I have checked interrupt attachment
with sin and find that the graphic processes have not attached to
interrupts. I think, also, that someone at qnx told me that the
banchee cards don’t use interrupts.


On Tue, 04 Sep 2001 20:53:04 GMT, Alex Cellarius
<acellarius@systems104.co.za> wrote:

On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest” <> mcharest@zinformatic.com> > wrote:
Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

Do the graphics cards use an IRQ?
Most times I’ve looked show_pci or similar shows IRQ as not connected for the VGA?

8

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
too complex.

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”
<mcharest@zinformatic.com> wrote:

“Greg Laird” <> glaird@teleport.com> > wrote in message
news:> 3b94e6ee.3176587@inn.qnx.com> …
This must be what is going on. Do you know how I might get around
this?


Beware that when you move windowsaround you affect sac and possibly how
it averages numbers. What you might be seeing are normal interrupt
(network,
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 > :wink:

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,
Greg Laird



On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest”
mcharest@zinformatic.com> > wrote:

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

“Greg Laird” <> glaird@pacifier.com> > wrote in message
news:> 3b941279.77606@inn.qnx.com> …
Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28. I
have my interrupt servicing process running at priority 29 and have
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 to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running at
pri 29. Proc32 is 28 and there are other processes in the low 20’s.

Now, all of this works fine until I start to move windows around with
Photon. I should say that the photon processes (input, crt drivers,
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 in a
while, a process with a priority greater than 30 runs when I am moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30, so my
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,
Greg Laird


\

9

Hi Dave,
I am using the Pg.Banshee driver that is dated May 31, 2000. I don’t
know if this is the most current, or how I would even find out.

Is there a list of current drivers and their creation dates somewhere?

Thanks,
Greg


On 4 Sep 2001 15:26:01 GMT, David Donohoe <ddonohoe@qnx.com> wrote:

Mario Charest <> mcharest@zinformatic.com> > wrote:
Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

Usually if they do, it is a graphics driver bug. There was a bug
in the Banshee driver at one point, where it was not polling its
FIFO correctly, and writes to the draw engine registers were
blocking (the adapter would put wait states onto the bus).

I’m not sure if the fix has made into QNX4 yet; make sure you have
the latest patch. Also, it might be worth trying a different
video card, just to narrow things down.

Dave

“Greg Laird” <> glaird@pacifier.com> > wrote in message
news:> 3b941279.77606@inn.qnx.com> …
Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28. I
have my interrupt servicing process running at priority 29 and have
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 to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running at
pri 29. Proc32 is 28 and there are other processes in the low 20’s.

Now, all of this works fine until I start to move windows around with
Photon. I should say that the photon processes (input, crt drivers,
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 in a
while, a process with a priority greater than 30 runs when I am moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30, so my
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,
Greg Laird

10

Hi Greg,

Unfortunately, the problem was only fixed in Oct, 2000, so we’ll
have to update the QNX4 banshee driver at some point with this
fix.

E.


Greg Laird <glaird@teleport.com> wrote:

As far as I know, the banchee cards do not use interrupts. I am using
two banchee cards in my system and show_pci indicates that they are
configred to use interrupt 11. I have checked interrupt attachment
with sin and find that the graphic processes have not attached to
interrupts. I think, also, that someone at qnx told me that the
banchee cards don’t use interrupts.



On Tue, 04 Sep 2001 20:53:04 GMT, Alex Cellarius
acellarius@systems104.co.za> > wrote:

On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest” <> mcharest@zinformatic.com> > wrote:
Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

Do the graphics cards use an IRQ?
Most times I’ve looked show_pci or similar shows IRQ as not connected for the VGA?

11

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).

-----Original Message-----
From: glaird@teleport.com (Greg Laird) [mailto:glaird@teleport.com]
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
too complex.

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”
<mcharest@zinformatic.com> wrote:

“Greg Laird” <> glaird@teleport.com> > wrote in message
news:> 3b94e6ee.3176587@inn.qnx.com> …
This must be what is going on. Do you know how I might get around
this?


Beware that when you move windowsaround you affect sac and possibly how
it averages numbers. What you might be seeing are normal interrupt
(network,
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 > :wink:

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,
Greg Laird



On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest”
mcharest@zinformatic.com> > wrote:

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

“Greg Laird” <> glaird@pacifier.com> > wrote in message
news:> 3b941279.77606@inn.qnx.com> …
Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application
that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28.
I
have my interrupt servicing process running at priority 29 and
have
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
to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running
at
pri 29. Proc32 is 28 and there are other processes in the low
20’s.

Now, all of this works fine until I start to move windows around
with
Photon. I should say that the photon processes (input, crt
drivers,
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
in a
while, a process with a priority greater than 30 runs when I am
moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30,
so my
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,
Greg Laird


\

12

The proxy has a priority of 29, and the flags are set to queue the
proxies in priority order. I don’t have priority float set as the
main process runs at pri 29.

I think the problem is with the graphics driver as the poster from qnx
indicates.



On Thu, 6 Sep 2001 11:58:08 -0700, Rennie Allen <RAllen@csical.com>
wrote:

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).

-----Original Message-----
From: > glaird@teleport.com > (Greg Laird) [mailto:> glaird@teleport.com> ]
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
too complex.

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”
mcharest@zinformatic.com> > wrote:


“Greg Laird” <> glaird@teleport.com> > wrote in message
news:> 3b94e6ee.3176587@inn.qnx.com> …
This must be what is going on. Do you know how I might get around
this?


Beware that when you move windowsaround you affect sac and possibly how
it averages numbers. What you might be seeing are normal interrupt
(network,
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 > :wink:

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,
Greg Laird



On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest”
mcharest@zinformatic.com> > wrote:

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

“Greg Laird” <> glaird@pacifier.com> > wrote in message
news:> 3b941279.77606@inn.qnx.com> …
Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application
that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28.
I
have my interrupt servicing process running at priority 29 and
have
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
to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running
at
pri 29. Proc32 is 28 and there are other processes in the low
20’s.

Now, all of this works fine until I start to move windows around
with
Photon. I should say that the photon processes (input, crt
drivers,
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
in a
while, a process with a priority greater than 30 runs when I am
moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30,
so my
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,
Greg Laird



\

13

Yeah, it’s just that setting the prio to 29, after attaching the proxy
(usually at 10) is a common mistake.

-----Original Message-----
From: glaird@teleport.com (Greg Laird) [mailto:glaird@teleport.com]
Posted At: Thursday, September 06, 2001 1:29 PM
Posted To: qnx4
Conversation: What runs at priority > 30?
Subject: Re: What runs at priority > 30?


The proxy has a priority of 29, and the flags are set to queue the
proxies in priority order. I don’t have priority float set as the
main process runs at pri 29.

I think the problem is with the graphics driver as the poster from qnx
indicates.



On Thu, 6 Sep 2001 11:58:08 -0700, Rennie Allen <RAllen@csical.com>
wrote:

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).

-----Original Message-----
From: > glaird@teleport.com > (Greg Laird) [mailto:> glaird@teleport.com> ]
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
too complex.

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”
mcharest@zinformatic.com> > wrote:


“Greg Laird” <> glaird@teleport.com> > wrote in message
news:> 3b94e6ee.3176587@inn.qnx.com> …
This must be what is going on. Do you know how I might get around
this?


Beware that when you move windowsaround you affect sac and possibly
how
it averages numbers. What you might be seeing are normal interrupt
(network,
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 > :wink:

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,
Greg Laird



On Tue, 4 Sep 2001 07:41:52 -0400, “Mario Charest”
mcharest@zinformatic.com> > wrote:

Priority 31 are interrupts.

Many graphics card will hold the bus for a “long” time during
graphic activity.

“Greg Laird” <> glaird@pacifier.com> > wrote in message
news:> 3b941279.77606@inn.qnx.com> …
Hi,
Hello,
I am using qnx 4.25 (december 2000 cd). I have an application
that
services an interrupt (which occurs at 16KHz) running on a 750Mhz
Athelon. I have rebuilt the OS, setting Proc32’s priority to 28.
I
have my interrupt servicing process running at priority 29 and
have
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
to
start the interrupt service routine.

Using sin, it appears that my routine is the only process running
at
pri 29. Proc32 is 28 and there are other processes in the low
20’s.

Now, all of this works fine until I start to move windows around
with
Photon. I should say that the photon processes (input, crt
drivers,
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
in a
while, a process with a priority greater than 30 runs when I am
moving
the windows around. This >30 priority process seems to occur at
about the same rate that my interrupt service routine misses
interrupts.

I imagine that some process is starting up with a priority > 30,
so my
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,
Greg Laird



\