1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
open Posix.Signal MLton.Signal
(* Translated from prodcons.ocaml. *)
fun for (start, stop, f) =
let
fun loop i =
if i > stop
then ()
else (f i; loop (i + 1))
in
loop start
end
fun print s = ()
structure Queue:
sig
type 'a t
val new: unit -> 'a t
val enque: 'a t * 'a -> unit
val deque: 'a t -> 'a option
end =
struct
datatype 'a t = T of {front: 'a list ref, back: 'a list ref}
fun new () = T {front = ref [], back = ref []}
fun enque (T {back, ...}, x) = back := x :: !back
fun deque (T {front, back}) =
case !front of
[] => (case !back of
[] => NONE
| l => let val l = rev l
in case l of
[] => raise Fail "deque"
| x :: l => (back := []; front := l; SOME x)
end)
| x :: l => (front := l; SOME x)
end
structure Thread:
sig
val exit: unit -> 'a
val run: unit -> unit
val spawn: (unit -> unit) -> unit
val yield: unit -> unit
structure Mutex:
sig
type t
val new: unit -> t
val lock: t * string -> unit
val unlock: t -> unit
end
structure Condition:
sig
type t
val new: unit -> t
val signal: t -> unit
val wait: t * Mutex.t -> unit
end
end =
struct
open MLton
open Itimer Signal Thread
val topLevel: Thread.Runnable.t option ref = ref NONE
local
val threads: Thread.Runnable.t Queue.t = Queue.new ()
in
fun ready t: unit = Queue.enque (threads, t)
fun next () : Thread.Runnable.t =
case Queue.deque threads of
NONE => (print "switching to toplevel\n"
; valOf (!topLevel))
| SOME t => t
end
fun 'a exit (): 'a = switch (fn _ => next ())
fun new (f: unit -> unit): Thread.Runnable.t =
Thread.prepare
(Thread.new (fn () => ((f () handle _ => exit ())
; exit ())),
())
fun schedule t =
(print "scheduling\n"
; ready t
; next ())
fun yield (): unit = switch (fn t => schedule (Thread.prepare (t, ())))
val spawn = ready o new
fun setItimer t =
Itimer.set (Itimer.Real,
{value = t,
interval = t})
fun run (): unit =
(switch (fn t =>
(topLevel := SOME (Thread.prepare (t, ()))
; new (fn () => (setHandler (alrm, Handler.handler schedule)
; setItimer (Time.fromMilliseconds 20)))))
; setItimer Time.zeroTime
; ignore alrm
; topLevel := NONE)
structure Mutex =
struct
datatype t = T of {locked: bool ref,
waiting: unit Thread.t Queue.t}
fun new () =
T {locked = ref false,
waiting = Queue.new ()}
fun lock (T {locked, waiting, ...}, name) =
let
fun loop () =
(print (concat [name, " lock looping\n"])
; Thread.atomicBegin ()
; if !locked
then (print "mutex is locked\n"
; switch (fn t =>
(Thread.atomicEnd ()
; Queue.enque (waiting, t)
; next ()))
; loop ())
else (print "mutex is not locked\n"
; locked := true
; Thread.atomicEnd ()))
in loop ()
end
fun safeUnlock (T {locked, waiting, ...}) =
(locked := false
; (case Queue.deque waiting of
NONE => ()
| SOME t => (print "unlock found waiting thread\n"
; ready (Thread.prepare (t, ())))))
fun unlock (m: t) =
(print "unlock atomicBegin\n"
; Thread.atomicBegin ()
; safeUnlock m
; Thread.atomicEnd ())
end
structure Condition =
struct
datatype t = T of {waiting: unit Thread.t Queue.t}
fun new () = T {waiting = Queue.new ()}
fun wait (T {waiting, ...}, m) =
(switch (fn t =>
(Mutex.safeUnlock m
; print "wait unlocked mutex\n"
; Queue.enque (waiting, t)
; next ()))
; Mutex.lock (m, "wait"))
fun signal (T {waiting, ...}) =
case Queue.deque waiting of
NONE => ()
| SOME t => ready (Thread.prepare (t, ()))
end
end
structure Mutex = Thread.Mutex
structure Condition = Thread.Condition
val count = ref 0
val data = ref 0
val produced = ref 0
val consumed = ref 0
val m = Mutex.new ()
val c = Condition.new ()
fun producer n =
for (1, n, fn i =>
(print (concat ["producer acquiring lock ", Int.toString i, "\n"])
; Mutex.lock (m, "producer")
; print "producer acquired lock\n"
; while !count = 1 do Condition.wait (c, m)
; print "producer passed condition\n"
; data := i
; count := 1
; Condition.signal c
; print "producer releasing lock\n"
; Mutex.unlock m
; print "producer released lock\n"
; produced := !produced + 1))
fun consumer n =
let val i = ref 0
in
while !i <> n do
(print (concat ["consumer acquiring lock ", Int.toString (!i), "\n"])
; Mutex.lock (m, "consumer")
; print "consumer acquired lock\n"
; while !count = 0 do Condition.wait (c, m)
; i := !data
; count := 0
; Condition.signal c
; print "consumer releasing lock\n"
; Mutex.unlock m
; print "consumer released lock\n"
; consumed := !consumed + 1)
end
fun atoi s = case Int.fromString s of SOME num => num | NONE => 0
fun printl [] = TextIO.print "\n" | printl (h::t) = ( TextIO.print h ; printl t )
fun main (name, args) =
let
val n = atoi (hd (args @ ["1"]))
val p = Thread.spawn (fn () => producer n)
val c = Thread.spawn (fn () => consumer n)
val _ = Thread.run ()
val _ = Posix.Process.sleep (Time.fromSeconds 1)
val _ = printl [Int.toString (!produced),
" ",
Int.toString (!consumed)]
in
()
end
val _ = main ( "prodcons", ["100000"] )
|
