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Billy Laws
47619063c2
Shared code buffer support introduced the concept of having a single GuestToHostMaps shared across many threads. In the common case all threads will share one however if e.g. a resize recently occured and specific thread is yet to compile any code with the new codebuffer it will still use the old GuestToHostMap. The current invalidation approach handles this by repeatedly calling erase for every single thread's GuestToHostMap, even if it is repeated. An accumulator is used to ensure when two threads share a map, the L1/L2 cache entries in the second thread will still be invalidated even if the the iteration for the first thread removed them from the map. Unfortunately this is incredibly slow in cases with many threads, as a significant number of redundant map lookups and L1/L2 cache erasures on threads that never even observed a given block can occur. Solve this by introducing a two-pass model: - First, all active codebuffers (and their associated GuestToHostMaps) have their entries invalidated for the given range, these codebuffers are tracked internally within FEXCore. It is at this point that delinking callbacks are ran. - Second, each thread will have its caches invalidated. But rather than naively invalidating the L1/L2 caches for every invalidated block for every thread, threads now track on their own what specific entries have been potentially fetched into their L1/L2 caches. This is aided by GuestToHostMap now tracking the pages each block touches. (an inverse CodePages so to speak).