RE: [Qemu-devel] VLIW?

[Gibbons, Scott]

My architecture is an Interleaved Multithreading VLIW architecture.  One bundle 
(packet) executes per processor cycle, rotating between threads (i.e., thread 0 
executes at time 0, thread 1 executes at time 1, then thread 0 executes at time 
2, etc.).  Each thread has its own context (including a program counter).  I'm 
not sure what kind of performance I would get in translating a single bundle at 
a time (or maybe I'm misunderstanding).

I think I'll get basic single-thread operation working first, then attempt 
multithreading when I have a spare month or so.

Thanks,
--Scott

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-----Original Message-----
From: Richard Henderson [mailto:address@hidden On Behalf Of Richard Henderson
Sent: Thursday, June 17, 2010 11:03 AM
To: Gibbons, Scott
Cc: address@hidden
Subject: Re: [Qemu-devel] VLIW?

On 06/17/2010 08:12 AM, Gibbons, Scott wrote:
> Another question I have is how to handle this multithreaded
> architecture.  This seems to be extraordinarily difficult as a
> dynamic translation problem and I'll probably defer it to later.
> But, if anyone has any suggestions, I'd be glad to hear them.

How is your threading different from other SMP systems?

In system mode, QEMU TCG is single-threaded and models SMP via
cooperative switching in between TCG translation blocks.  It's
not ideal, but it does solve quite a number of problems and is
at least functional.


r~