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Light on PPC interrupt management requested
- Date: Tue, 09 Feb 1999 12:39:06 +0100 (MET)
- From: jzamora at avellano.datsi.fi.upm.es (Juan Zamorano Flores)
- Subject: Light on PPC interrupt management requested
> Benefits : if you sitch from one thread that use the FPU to another that
> do not, you do not need to save the FPU registers. If the threads takes
> that own the FPU register is shdeuled again, you will just reenable the FPU
> with no need of restoring the FPU registers...
I am sorry for the intrusion but I think we can't forget that RTEMS
means Real Time Ex...
The above is not a benefit for a real time OS: Real time computing is not
fast computing but predictable computing (J. Stankovic Missconceptions
about Real-Time computing).
In order to avoid context switching overload that approach will overload
the estimate computation time of the task which uses the FPU. I think that
approach raises the indeterminist of the OS services.
I think that the true feature of a RT OS is that the OS services have
an upper bounded computation time.
So I think that the simple approach (to save FPU register in context
switch for a FP task) will produce better RT behaviour.
Just my 2 cents (of euro)