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Clarifying

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svn: r6622
This commit is contained in:
Jay McCarthy 2007-06-13 01:55:26 +00:00
parent e433ec1144
commit 2445c88ed8
2 changed files with 14 additions and 15 deletions
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19
collects/web-server/docs/reference/managers.scrbl
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@ -113,14 +113,13 @@ deployments of the @web-server .
@file{managers/lru.ss} defines a manager constructor:
@; XXX Rename time0 and time1
@; XXX Cite Continue
@defproc[(create-LRU-manager
[instance-expiration-handler expiration-handler?]
[time0 integer?]
[time1 integer?]
[collect? (-> boolean?)]
[#:initial-count initial-count integer? 1]
[instance-expiration-handler expiration-handler?]
[check-interval integer?]
[collect-interval integer?]
[collect? (-> boolean?)]
[#:initial-count initial-count integer? 1]
[#:inform-p inform-p (integer? . -> . void) (lambda _ (void))])
manager?]{
Instances managed by this manager will be expired if there are no
@ -135,8 +134,8 @@ deployments of the @web-server .
is thrown with @scheme[instance-exp-handler] as the expiration handler, if
no expiration-handler was passed to @scheme[continuation-store!].
Every @scheme[time0] seconds @scheme[collect?] is called to determine
if the collection routine should be run. Every @scheme[time1] seconds
Every @scheme[check-interval] seconds @scheme[collect?] is called to determine
if the collection routine should be run. Every @scheme[collect-interval] seconds
the collection routine is run.
Every time the collection routine runs, the "Life Count" of every
@ -148,8 +147,8 @@ deployments of the @web-server .
The recommended use of this manager is to pass, as @scheme[collect?], a
function that checks the memory usage of the system, through
@scheme[current-memory-use]. Then, @scheme[time1] should be sufficiently
large compared to @scheme[time0]. This way, if the load on the server
@scheme[current-memory-use]. Then, @scheme[collect-interval] should be sufficiently
large compared to @scheme[check-interval]. This way, if the load on the server
spikes---as indicated by memory usage---the server will quickly expire
continuations, until the memory is back under control. If the load
stays low, it will still efficiently expire old continuations.

10
collects/web-server/managers/lru.ss
View File

@ -20,7 +20,7 @@
next-instance-id))
(define/kw (create-LRU-manager
instance-expiration-handler
time0 time1
check-interval collect-interval
collect?
#:key
[initial-count 1]
@ -154,18 +154,18 @@
(define (seconds->msecs s)
(+ (current-inexact-milliseconds)
(* s 1000)))
(let loop ([msecs0 (seconds->msecs time0)]
[msecs1 (seconds->msecs time1)])
(let loop ([msecs0 (seconds->msecs check-interval)]
[msecs1 (seconds->msecs collect-interval)])
(sync (handle-evt
(alarm-evt msecs0)
(lambda _
(when (collect?)
(collect #f))
(loop (seconds->msecs time0) msecs1)))
(loop (seconds->msecs check-interval) msecs1)))
(handle-evt
(alarm-evt msecs1)
(lambda _
(collect #t)
(loop msecs0 (seconds->msecs time1)))))))))
(loop msecs0 (seconds->msecs collect-interval)))))))))
the-manager))