Metagence

[PC-Engine]

Does anyone know if the Metagence DSPs from Imgtech are based on SMT?

Kristof or Simon?

 

[Kristof]

What is SMT ?

You have to remember that both Simon and I are part of the PowerVR Division and as such not up to speed on the Metagence side.

K-

 

[PC-Engine]

Hi Kristof, it stands for Simultaneous Multithreading. I'm sure you're familar with that term but were probably thinking about something else? Sorry if this thread doesn't belong here, but I was really in a hurry to find an answer

 

[Kristof]

I know there is a patent, maybe you should look at that ? I really know nothing about meta except for its applications and even thats from the press material

http://www.metagence.co.uk/Technology.asp

The memory system and caches of the DSP core are fully multi-threaded to allow operation at maximum efficiency. The execution of instructions from threads is scheduled on a clock by clock basis, resulting in zero overhead for the switch from one thread to another and instant response to external stimuli. A control system is provided to monitor and adjust the instruction issue rate of each thread to allow overall system real-time constraints to be met.

K-

 

[PC-Engine]

Cool thanks, I guess Intel, Compaq, and AMD are kinda late to the game then

You PowerVR guys work in a locked dungeon or what?

 

[arjan de lumens]

Hmmm .. simultaneous multithreading is not at all a new idea - this posting at ace's hardware indicates that the idea appeared for the first time no later than 1974 (!).

 

[PC-Engine]

Thanks

 

[psurge]

Kristof, sounds like either FMT or SMT... Can instructions from multiple threads be issued in the same clock cycle? Can instructions from multiple threads occupy the same pipeline stage simultaneously?

A good explanation of SMT : here

 

[JohnH]

Only one thread can be executing in any one clock. Parallel use of pipeline stages is a little more difficult to answer as I'm not sure what you would consider a pipeline stage. However any one thread can execute at full instruction rate if not stalled waiting for some resource and that there is no penalty switching between threads i.e utilisation is 100% irrespective of thread switching as long as at least one thread is able to proceed.

John.