Data commit

Task/Checkpoint-synchronization/Racket/checkpoint-synchronization-1.rkt

@@ -0,0 +1,44 @@
+#lang racket
+(define t 5)     ; total number of threads
+(define count 0) ; number of threads arrived at rendezvous
+(define mutex      (make-semaphore 1)) ; exclusive access to count
+(define turnstile  (make-semaphore 0))
+(define turnstile2 (make-semaphore 1))
+(define ch (make-channel))
+
+(define (make-producer name start)
+  (λ ()
+    (let loop ([n start])
+      (sleep (* 0.01 (random 10))) ; "compute" something
+      ;; rendezvous
+      (semaphore-wait mutex)
+      (set! count (+ count 1)) ; we have arrived
+      (when (= count t) ; are we the last to arrive?
+        (semaphore-wait turnstile2)
+        (semaphore-post turnstile))
+      (semaphore-post mutex)
+      ; avoid deadlock problem:
+      (semaphore-wait turnstile)
+      (semaphore-post turnstile)
+      ; critical point
+      (channel-put ch n) ; send result to controller
+      ; leave properly
+      (semaphore-wait mutex)
+      (set! count (- count 1))
+      (when (= count 0) ; are we the last to leave?
+        (semaphore-wait turnstile)
+        (semaphore-post turnstile2))
+      (semaphore-post mutex)
+
+      (semaphore-wait turnstile2)
+      (semaphore-post turnstile2)
+
+      (loop (+ n t)))))
+
+; start t workers:
+(map (λ(start) (thread (make-producer start start)))
+     (range 0 t))
+
+(let loop ()
+  (displayln (for/list ([_ t]) (channel-get ch)))
+  (loop))

Task/Checkpoint-synchronization/Racket/checkpoint-synchronization-2.rkt

@@ -0,0 +1,21 @@
+(1 4 2 0 3)
+(6 9 7 8 5)
+(11 10 14 12 13)
+(16 15 18 19 17)
+(24 21 20 23 22)
+(29 25 28 27 26)
+(30 33 34 32 31)
+(37 38 39 35 36)
+(44 43 41 40 42)
+(46 45 48 49 47)
+(50 53 51 54 52)
+(56 57 58 55 59)
+(60 63 62 61 64)
+(66 69 65 68 67)
+(73 70 74 71 72)
+(78 77 76 79 75)
+(82 80 81 84 83)
+(87 89 88 86 85)
+(92 93 90 91 94)
+(97 98 99 95 96)
+...