[geeks] Game GPU clusters for supercomputering

[Sridhar Ayengar]

Joshua Boyd wrote:
> As you can imagine, between the 128x128 register file, and the SRAM, a
> context switch on a SPE is horrendous.  This means that in a
> multitasking environment SPEs can't really be shared between
> applications, so if you have a video player that uses 2 SPEs, it grabs
> those SPEs and doesn't release them until you stop it.

Is there anything stopping one from just requesting SPEs and releasing 
them as if you were starting up and shutting down on a process level? 
As in, is it possible to dynamically allocate SPEs with really, really 
coarse granularity?

Say, if said video app is playing, happily running along on two SPEs, 
but then you hit stop.  Could it let go of those two SPEs until you hit 
play again?  I understand that there would be a big pile of overhead 
involved, but would the cost of the overhead outweigh the benefit from 
relinquishing the SPEs for a few seconds?

Peace...  Sridhar