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cs: adjust trigger major GC

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Commit 1811193285 caused Racket CS to have much higher peak memory
use. Adjust the heuristic again to trigger a major GC when the
`current-memory-bytes` value is the post-GC `bytes-allocated` plus the
post-GC `current-memory-bytes`, which means waiting until
another `bytes-allocated` bytes are allocated (instead of waiting
until the number of newly allocated bytes also catches up to overhead,
such as unserused pages due to locked objects).
This commit is contained in:
Matthew Flatt 2019-09-04 21:08:12 -06:00
parent 91d702c6fe
commit 1f2342b57a
1 changed files with 9 additions and 4 deletions
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13
racket/src/cs/rumble/memory.ss
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@ -34,7 +34,7 @@
(define gc-counter 1)
(define log-collect-generation-radix 2)
(define collect-generation-radix-mask (sub1 (bitwise-arithmetic-shift 1 log-collect-generation-radix)))
(define allocated+overhead-after-major (* 32 1024 1024))
(define trigger-major-gc-memory-bytes (* 32 1024 1024))
(define non-full-gc-counter 0)
;; Called in any thread with all other threads paused. The Racket
@ -52,7 +52,7 @@
(set! gc-counter (add1 this-counter)))
(let ([gen (cond
[(and (not g)
(or (>= pre-allocated+overhead (* 2 allocated+overhead-after-major))
(or (>= pre-allocated+overhead trigger-major-gc-memory-bytes)
(>= non-full-gc-counter 10000)))
;; Force a major collection if memory use has doubled
(collect-maximum-generation)]
@ -68,7 +68,12 @@
(let ([post-allocated (bytes-allocated)]
[post-allocated+overhead (current-memory-bytes)])
(when (= gen (collect-maximum-generation))
(set! allocated+overhead-after-major post-allocated+overhead))
;; Trigger a major GC when twice as much memory is used. Twice
;; `post-allocated+overhead` seems to be too long a wait, because
;; that value may include underused pages that have locked objects.
;; Using just `post-allocated` is too small, because it may force an
;; immediate major GC too soon. Split the difference.
(set! trigger-major-gc-memory-bytes (+ post-allocated post-allocated+overhead)))
(garbage-collect-notify gen
pre-allocated pre-allocated+overhead pre-time pre-cpu-time
post-allocated post-allocated+overhead (real-time) (cpu-time)))
@ -357,7 +362,7 @@
(define/who (make-phantom-bytes k)
(check who exact-nonnegative-integer? k)
(let ([ph (create-phantom-bytes (make-phantom-bytevector k))])
(when (>= (current-memory-bytes) (* 2 allocated+overhead-after-major))
(when (>= (current-memory-bytes) trigger-major-gc-memory-bytes)
(collect-garbage))
ph))