Yes, it's not a new idea. See Microsoft Singularity research OS for a more recent example.
You would still have slower than native execution speed, security problems with Spectre attacks (in HW process isolation it's avoided by not having other memory mapped at all, other mitigations exist but they cost a lot of performance).
Syscall speedups affect only specific programs or stupidly written SW like some games that are checking current time many many times per frame.
You would still have slower than native execution speed, security problems with Spectre attacks (in HW process isolation it's avoided by not having other memory mapped at all, other mitigations exist but they cost a lot of performance).
Syscall speedups affect only specific programs or stupidly written SW like some games that are checking current time many many times per frame.