Do you need a cache?
If you are hiding a 128 clocks of memory latency, do you need a data cache?
- Tera’s answer => NO!
- All memory is equally accessible (or inaccessible) by all processors - memory is one, large flat space.
So how do you use all of the extra silicon space that you save by not having a data cache on the CPU?
- You use it to implement the 128 contexts!
- Need 128 copies of the register files and internal registers (i.e, shelving buffers, ROB, etc). This requires a LOT of space.
- Do not need multiple copies of execution units.