Michael Gottesman b5ce28fc57 [region-isolation] Cache getUnderlyingTrackedValue. ...

TLDR: Was looking at some performance traces and saw that we need to cache the
result of this value.

----

Specifically, I noticed that we were spending a lot of time computing this
operation. When I looked at the code I saw that we already had a cache along the
relevant code paths... but the cache was from equivalence class representative
-> state. Before we hit that cache, we were performing the work to map the value
to the equivalence class representative... so the work to perform the relevant
lookup from value -> state (which goes through the equivalence class
representative) was not just a hash table lookup. This operation makes it
cheaper by making it two cache lookups.

It may be possible to make this cheaper by redoing the actual mapping of
information so that we can go straight from value to state. I think it would be
slightly different since we would probably need to represent the state in a
separate array and map with indices... which is really just a more efficient
hash table. We could also use malloc/etc but lets not even talk about that.

rdar://139520959

2024-11-11 11:43:07 -08:00

20 KiB

Raw Blame History

View Raw