> An MMU could dramatically improve unit performance. Basically,
> DmWriteCheck (which is called a lot) is doing in software what a MMU
> could do more reliably in hardware.
Could it really? How? Let alone that MMUs typically only protect on a page
sizes, not byte sizes (which you'd want in order to protect individual chunk).
Let alone trying to keep the protection ranges in sync with the heap layout
(through memory allocations, compactions, deletions, etc.). But how would
DmWrite be faster? It would still have to reprogram the MMU to allow writes to
the specified memory location. Would that reprogramming be any faster than
what's done now?
Are you thinking of some radically different scheme than what's used now?
Perhaps one where each application more or less gets its own storage heap that
it's free to unprotect and (possibly) corrupt?
I think that the real problem is that people feel they are constrained by the
size of the dynamic heap, and so use DmWrite to get access to more memory. So
the real solution is not to speed up DmWrite, but to allow larger dynamic heaps,
and maybe different ones per application. Perhaps that's the problem that an
MMU could be used to solve. Any ideas here?
-- Keith
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