From e8c779736f3029df353038352c14c8ab63728811 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Thu, 1 Nov 2018 13:21:00 -0300 Subject: Removed internal cache for closures The mechanism of "caching the last closure created for a prototype to try to reuse it the next time a closure for that prototype is created" was removed. There are several reasons: - It is hard to find a natural example where this cache has a measurable impact on performance. - Programmers already perceive closure creation as something slow, so they tend to avoid it inside hot paths. (Any case where the cache could reuse a closure can be rewritten predefining the closure in some variable and using that variable.) - The implementation was somewhat complex, due to a bad interaction with the generational collector. (Typically, new closures are new, while prototypes are old. So, the cache breaks the invariant that old objects should not point to new ones.) --- lobject.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'lobject.h') diff --git a/lobject.h b/lobject.h index ea3511de..df31a1a0 100644 --- a/lobject.h +++ b/lobject.h @@ -505,7 +505,6 @@ typedef struct Proto { lu_byte numparams; /* number of fixed (named) parameters */ lu_byte is_vararg; lu_byte maxstacksize; /* number of registers needed by this function */ - lu_byte cachemiss; /* count for successive misses for 'cache' field */ int sizeupvalues; /* size of 'upvalues' */ int sizek; /* size of 'k' */ int sizecode; @@ -516,7 +515,6 @@ typedef struct Proto { int linedefined; /* debug information */ int lastlinedefined; /* debug information */ TValue *k; /* constants used by the function */ - struct LClosure *cache; /* last-created closure with this prototype */ Instruction *code; /* opcodes */ struct Proto **p; /* functions defined inside the function */ Upvaldesc *upvalues; /* upvalue information */ -- cgit v1.2.3-55-g6feb