I've wondered for a while whether it would make sense to split the CPU into a "IOPU" and a "SPU"
- The IOPU would be responsible for directing other hardware on the system. It doesn't need to be very performant.
- The SPU would be optimized for scalar and branch-heavy code that needs to run fast.
The SPU could have minimal security, just enough so it can't read arbitrary memory when fetching from RAM. It would only run one program at a time, so speculation shouldn't be an issue.
At least on my system few programs need a lot of processing power (and even then only intermittently), so little task switching should occur on an SPU.
- The IOPU would be responsible for directing other hardware on the system. It doesn't need to be very performant.
- The SPU would be optimized for scalar and branch-heavy code that needs to run fast.
The SPU could have minimal security, just enough so it can't read arbitrary memory when fetching from RAM. It would only run one program at a time, so speculation shouldn't be an issue.
At least on my system few programs need a lot of processing power (and even then only intermittently), so little task switching should occur on an SPU.