The attached (highly experimental) patch seems to improve the
performance of normal sends (in the case of a cache hit) by roughly 100%
- 150%. The difference between this mere factor of two improvement and
the factor of six-through-ten I was seeing earlier is, I speculate,
related to object-ref taking a lot of time.
Interestingly, the performance of (send something message) is, with this
patch, seemingly roughly en par with the performance of generics
captured using generic and invoked using send-generic.
I haven't yet tried running a full racket system with this patch
applied. I wonder if it makes a difference to the interactive
performance of DrRacket?
Major weaknesses of the approach:
- overhead on cache miss is unknown
- not safe-for-space yet (weak boxes are immutable)
The approach should generalize easily to polymorphic inline caches.
Regards,
Tony
diff --git a/collects/racket/private/class-internal.rkt
b/collects/racket/private/class-internal.rkt
index d00ef10..0a96cba 100644
--- a/collects/racket/private/class-internal.rkt
+++ b/collects/racket/private/class-internal.rkt
@@ -3734,19 +3734,30 @@
(let ()
(define (do-method traced? stx form obj name args rest-arg?)
- (with-syntax ([(sym method receiver)
- (generate-temporaries (syntax (1 2 3)))])
+ (with-syntax ([(sym in-object in-class state method receiver)
+ (generate-temporaries (syntax (1 2 3 4 5 6)))]
+ [*cached-state*
+ (syntax-local-lift-expression
+ (syntax (cons #f #f)))])
(quasisyntax/loc stx
(let*-values ([(sym) (quasiquote (unsyntax (localize name)))]
- [(method receiver)
- (find-method/who '(unsyntax form)
- (unsyntax obj)
- sym)])
+ [(in-object) (unsyntax obj)]
+ [(in-class) (and (object? in-object) (object-ref
in-object))]
+ [(state) *cached-state*]
+ [(method)
+ (if (and in-class (eq? (car state) in-class))
+ (cdr state)
+ (let-values ([(m r)
+ (find-method/who '(unsyntax form)
+ in-object
+ sym)])
+ (set! *cached-state* (cons in-class m))
+ m))])
(unsyntax
(make-method-call
traced?
stx
- (syntax/loc stx receiver)
+ (syntax/loc stx in-object)
(syntax/loc stx method)
(syntax/loc stx sym)
args
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