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Priority selection for application

Discussion about the general applications that run on QNX6

Priority selection for application

Postby hello » Mon Apr 22, 2013 1:26 pm

Hi all,

By default, the priority of a thread is 10. I need some of my threads to run at high priority. So i set their priorities at 20. But it caused some issues like the system time not getting updated etc.

From my understanding OS related threads are running at priorities 10 , 11 and 12 and driver threads at 21, 22 etc.
Could anyone please tell which priority range i should give for my application threads. Scheduling used in round robin.

Regards,
hello
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Re: Priority selection for application

Postby Tim » Mon Apr 22, 2013 4:49 pm

Just setting a thread to be 1 higher (11) than the default of 10 should be all you need. If that's not enough, try 12.

It's very rare that you would need priorities for an application (non-driver) beyond those numbers. In fact I hardly ever use anything but the default priority of 10.

Tim
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Re: Priority selection for application

Postby mario » Wed Apr 24, 2013 7:22 pm

And multi-core makes priority less relevant. We aren't that far away from machines with as many core as there are priorities ;-)
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Re: Priority selection for application

Postby maschoen » Thu Apr 25, 2013 6:40 am

mario wrote:And multi-core makes priority less relevant. We aren't that far away from machines with as many core as there are priorities ;-)


How about as many processors as running threads, :-).
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Re: Priority selection for application

Postby Tim » Thu Apr 25, 2013 4:27 pm

We are already there now aren't we?

AMD offers 16 core processors (Opteron 6200 series) and there are MB's that hold 4 of them giving 64 cores. The cost is around $4300 making them cost effective for servers / high end work stations.

http://www.thinkmate.com/Computer_Syste ... ore_Server

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Re: Priority selection for application

Postby maschoen » Thu Apr 25, 2013 4:38 pm

Tim wrote:We are already there now aren't we?

AMD offers 16 core processors (Opteron 6200 series) and there are MB's that hold 4 of them giving 64 cores. The cost is around $4300 making them cost effective for servers / high end work stations.

http://www.thinkmate.com/Computer_Syste ... ore_Server

Tim


Yes, but on a server you probably have 64+ threads running. I'm really nit picking here.
That's a tremendous amount of cpu power, and more than likely a system like that is completely
I/O bound at the disk(s).

I could be wrong, but I think the current distributions of QNX only have a cpu mask with 32 bits, so
I guess QNX is maxed out. It's probably something along the lines of getting a 64 bit version going before more are supported.
Of course with the current focus on embedded systems, that will probably be quite a while.
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Re: Priority selection for application

Postby mario » Thu Apr 25, 2013 6:21 pm

maschoen wrote:Of course with the current focus on embedded systems, that will probably be quite a while.


I hope not!
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Re: Priority selection for application

Postby maschoen » Fri Apr 26, 2013 1:24 am

mario wrote:
maschoen wrote:Of course with the current focus on embedded systems, that will probably be quite a while.


I hope not!


I had a talk today with someone from QNX. The told me that it was half done (64 bit QNX), but not in progress.
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