wenzelm@28156
|
1 |
(* Title: Pure/Concurrent/future.ML
|
wenzelm@28156
|
2 |
Author: Makarius
|
wenzelm@28156
|
3 |
|
wenzelm@32250
|
4 |
Future values, see also
|
wenzelm@32250
|
5 |
http://www4.in.tum.de/~wenzelm/papers/parallel-isabelle.pdf
|
wenzelm@38175
|
6 |
http://www4.in.tum.de/~wenzelm/papers/parallel-ml.pdf
|
wenzelm@28201
|
7 |
|
wenzelm@28201
|
8 |
Notes:
|
wenzelm@28201
|
9 |
|
wenzelm@28201
|
10 |
* Futures are similar to delayed evaluation, i.e. delay/force is
|
wenzelm@28201
|
11 |
generalized to fork/join (and variants). The idea is to model
|
wenzelm@28201
|
12 |
parallel value-oriented computations, but *not* communicating
|
wenzelm@28201
|
13 |
processes.
|
wenzelm@28201
|
14 |
|
wenzelm@28201
|
15 |
* Futures are grouped; failure of one group member causes the whole
|
wenzelm@32220
|
16 |
group to be interrupted eventually. Groups are block-structured.
|
wenzelm@28201
|
17 |
|
wenzelm@28201
|
18 |
* Forked futures are evaluated spontaneously by a farm of worker
|
wenzelm@28201
|
19 |
threads in the background; join resynchronizes the computation and
|
wenzelm@28201
|
20 |
delivers results (values or exceptions).
|
wenzelm@28201
|
21 |
|
wenzelm@28201
|
22 |
* The pool of worker threads is limited, usually in correlation with
|
wenzelm@28201
|
23 |
the number of physical cores on the machine. Note that allocation
|
wenzelm@28201
|
24 |
of runtime resources is distorted either if workers yield CPU time
|
wenzelm@28201
|
25 |
(e.g. via system sleep or wait operations), or if non-worker
|
wenzelm@28201
|
26 |
threads contend for significant runtime resources independently.
|
wenzelm@34277
|
27 |
|
wenzelm@34277
|
28 |
* Promised futures are fulfilled by external means. There is no
|
wenzelm@34277
|
29 |
associated evaluation task, but other futures can depend on them
|
wenzelm@34277
|
30 |
as usual.
|
wenzelm@28156
|
31 |
*)
|
wenzelm@28156
|
32 |
|
wenzelm@28156
|
33 |
signature FUTURE =
|
wenzelm@28156
|
34 |
sig
|
wenzelm@32823
|
35 |
val worker_task: unit -> Task_Queue.task option
|
wenzelm@32122
|
36 |
val worker_group: unit -> Task_Queue.group option
|
wenzelm@38133
|
37 |
val worker_subgroup: unit -> Task_Queue.group
|
wenzelm@28972
|
38 |
type 'a future
|
wenzelm@42563
|
39 |
val task_of: 'a future -> Task_Queue.task
|
wenzelm@28972
|
40 |
val peek: 'a future -> 'a Exn.result option
|
wenzelm@28972
|
41 |
val is_finished: 'a future -> bool
|
wenzelm@42563
|
42 |
val forks:
|
wenzelm@42563
|
43 |
{name: string, group: Task_Queue.group option, deps: Task_Queue.task list, pri: int} ->
|
wenzelm@42563
|
44 |
(unit -> 'a) list -> 'a future list
|
wenzelm@29120
|
45 |
val fork_pri: int -> (unit -> 'a) -> 'a future
|
wenzelm@32729
|
46 |
val fork: (unit -> 'a) -> 'a future
|
wenzelm@28972
|
47 |
val join_results: 'a future list -> 'a Exn.result list
|
wenzelm@28972
|
48 |
val join_result: 'a future -> 'a Exn.result
|
wenzelm@28972
|
49 |
val join: 'a future -> 'a
|
wenzelm@34277
|
50 |
val value: 'a -> 'a future
|
wenzelm@28972
|
51 |
val map: ('a -> 'b) -> 'a future -> 'b future
|
wenzelm@42563
|
52 |
val promise_group: Task_Queue.group -> 'a future
|
wenzelm@34277
|
53 |
val promise: unit -> 'a future
|
wenzelm@34277
|
54 |
val fulfill_result: 'a future -> 'a Exn.result -> unit
|
wenzelm@34277
|
55 |
val fulfill: 'a future -> 'a -> unit
|
wenzelm@30621
|
56 |
val interruptible_task: ('a -> 'b) -> 'a -> 'b
|
wenzelm@42563
|
57 |
val cancel_group: Task_Queue.group -> unit
|
wenzelm@28972
|
58 |
val cancel: 'a future -> unit
|
wenzelm@28203
|
59 |
val shutdown: unit -> unit
|
wenzelm@38492
|
60 |
val status: (unit -> 'a) -> 'a
|
wenzelm@28156
|
61 |
end;
|
wenzelm@28156
|
62 |
|
wenzelm@28156
|
63 |
structure Future: FUTURE =
|
wenzelm@28156
|
64 |
struct
|
wenzelm@28156
|
65 |
|
wenzelm@28177
|
66 |
(** future values **)
|
wenzelm@28177
|
67 |
|
wenzelm@28167
|
68 |
(* identifiers *)
|
wenzelm@28167
|
69 |
|
wenzelm@32074
|
70 |
local
|
wenzelm@42563
|
71 |
val tag = Universal.tag () : Task_Queue.task option Universal.tag;
|
wenzelm@32074
|
72 |
in
|
wenzelm@42563
|
73 |
fun worker_task () = the_default NONE (Thread.getLocal tag);
|
wenzelm@42563
|
74 |
fun setmp_worker_task data f x =
|
wenzelm@42563
|
75 |
Library.setmp_thread_data tag (worker_task ()) (SOME data) f x;
|
wenzelm@28167
|
76 |
end;
|
wenzelm@28167
|
77 |
|
wenzelm@42563
|
78 |
val worker_group = Option.map Task_Queue.group_of_task o worker_task;
|
wenzelm@38133
|
79 |
fun worker_subgroup () = Task_Queue.new_group (worker_group ());
|
wenzelm@34277
|
80 |
|
wenzelm@42559
|
81 |
fun worker_joining e =
|
wenzelm@42559
|
82 |
(case worker_task () of
|
wenzelm@42559
|
83 |
NONE => e ()
|
wenzelm@42559
|
84 |
| SOME task => Task_Queue.joining task e);
|
wenzelm@42559
|
85 |
|
wenzelm@42560
|
86 |
fun worker_waiting deps e =
|
wenzelm@42541
|
87 |
(case worker_task () of
|
wenzelm@42541
|
88 |
NONE => e ()
|
wenzelm@42560
|
89 |
| SOME task => Task_Queue.waiting task deps e);
|
wenzelm@42541
|
90 |
|
wenzelm@28167
|
91 |
|
wenzelm@28167
|
92 |
(* datatype future *)
|
wenzelm@28167
|
93 |
|
wenzelm@35016
|
94 |
type 'a result = 'a Exn.result Single_Assignment.var;
|
wenzelm@35016
|
95 |
|
wenzelm@28972
|
96 |
datatype 'a future = Future of
|
wenzelm@34277
|
97 |
{promised: bool,
|
wenzelm@42563
|
98 |
task: Task_Queue.task,
|
wenzelm@35016
|
99 |
result: 'a result};
|
wenzelm@28167
|
100 |
|
wenzelm@28167
|
101 |
fun task_of (Future {task, ...}) = task;
|
wenzelm@32257
|
102 |
fun result_of (Future {result, ...}) = result;
|
wenzelm@28167
|
103 |
|
wenzelm@35016
|
104 |
fun peek x = Single_Assignment.peek (result_of x);
|
wenzelm@28558
|
105 |
fun is_finished x = is_some (peek x);
|
wenzelm@28320
|
106 |
|
wenzelm@34277
|
107 |
fun assign_result group result res =
|
wenzelm@34277
|
108 |
let
|
wenzelm@38122
|
109 |
val _ = Single_Assignment.assign result res
|
wenzelm@38122
|
110 |
handle exn as Fail _ =>
|
wenzelm@38122
|
111 |
(case Single_Assignment.peek result of
|
wenzelm@39509
|
112 |
SOME (Exn.Exn e) => reraise (if Exn.is_interrupt e then e else exn)
|
wenzelm@38122
|
113 |
| _ => reraise exn);
|
wenzelm@34277
|
114 |
val ok =
|
wenzelm@38122
|
115 |
(case the (Single_Assignment.peek result) of
|
wenzelm@34277
|
116 |
Exn.Exn exn => (Task_Queue.cancel_group group exn; false)
|
wenzelm@34277
|
117 |
| Exn.Result _ => true);
|
wenzelm@34277
|
118 |
in ok end;
|
wenzelm@29002
|
119 |
|
wenzelm@28167
|
120 |
|
wenzelm@28177
|
121 |
|
wenzelm@28177
|
122 |
(** scheduling **)
|
wenzelm@28177
|
123 |
|
wenzelm@28177
|
124 |
(* synchronization *)
|
wenzelm@28156
|
125 |
|
wenzelm@32219
|
126 |
val scheduler_event = ConditionVar.conditionVar ();
|
wenzelm@32219
|
127 |
val work_available = ConditionVar.conditionVar ();
|
wenzelm@32219
|
128 |
val work_finished = ConditionVar.conditionVar ();
|
wenzelm@32219
|
129 |
|
wenzelm@28156
|
130 |
local
|
wenzelm@28156
|
131 |
val lock = Mutex.mutex ();
|
wenzelm@28156
|
132 |
in
|
wenzelm@28156
|
133 |
|
wenzelm@37216
|
134 |
fun SYNCHRONIZED name = Simple_Thread.synchronized name lock;
|
wenzelm@28156
|
135 |
|
wenzelm@32219
|
136 |
fun wait cond = (*requires SYNCHRONIZED*)
|
wenzelm@32298
|
137 |
Multithreading.sync_wait NONE NONE cond lock;
|
wenzelm@28206
|
138 |
|
wenzelm@32298
|
139 |
fun wait_timeout timeout cond = (*requires SYNCHRONIZED*)
|
wenzelm@32298
|
140 |
Multithreading.sync_wait NONE (SOME (Time.+ (Time.now (), timeout))) cond lock;
|
wenzelm@28166
|
141 |
|
wenzelm@32219
|
142 |
fun signal cond = (*requires SYNCHRONIZED*)
|
wenzelm@32219
|
143 |
ConditionVar.signal cond;
|
wenzelm@32219
|
144 |
|
wenzelm@32219
|
145 |
fun broadcast cond = (*requires SYNCHRONIZED*)
|
wenzelm@28166
|
146 |
ConditionVar.broadcast cond;
|
wenzelm@28156
|
147 |
|
wenzelm@32252
|
148 |
fun broadcast_work () = (*requires SYNCHRONIZED*)
|
wenzelm@32252
|
149 |
(ConditionVar.broadcast work_available;
|
wenzelm@32225
|
150 |
ConditionVar.broadcast work_finished);
|
wenzelm@32225
|
151 |
|
wenzelm@28156
|
152 |
end;
|
wenzelm@28156
|
153 |
|
wenzelm@28156
|
154 |
|
wenzelm@33431
|
155 |
(* global state *)
|
wenzelm@33431
|
156 |
|
wenzelm@33431
|
157 |
val queue = Unsynchronized.ref Task_Queue.empty;
|
wenzelm@33431
|
158 |
val next = Unsynchronized.ref 0;
|
wenzelm@33431
|
159 |
val scheduler = Unsynchronized.ref (NONE: Thread.thread option);
|
wenzelm@33431
|
160 |
val canceled = Unsynchronized.ref ([]: Task_Queue.group list);
|
wenzelm@33431
|
161 |
val do_shutdown = Unsynchronized.ref false;
|
wenzelm@33431
|
162 |
val max_workers = Unsynchronized.ref 0;
|
wenzelm@33431
|
163 |
val max_active = Unsynchronized.ref 0;
|
wenzelm@33432
|
164 |
val worker_trend = Unsynchronized.ref 0;
|
wenzelm@33431
|
165 |
|
wenzelm@33431
|
166 |
datatype worker_state = Working | Waiting | Sleeping;
|
wenzelm@33431
|
167 |
val workers = Unsynchronized.ref ([]: (Thread.thread * worker_state Unsynchronized.ref) list);
|
wenzelm@33431
|
168 |
|
wenzelm@33431
|
169 |
fun count_workers state = (*requires SYNCHRONIZED*)
|
wenzelm@33431
|
170 |
fold (fn (_, state_ref) => fn i => if ! state_ref = state then i + 1 else i) (! workers) 0;
|
wenzelm@33431
|
171 |
|
wenzelm@33431
|
172 |
|
wenzelm@32119
|
173 |
(* execute future jobs *)
|
wenzelm@32119
|
174 |
|
wenzelm@32119
|
175 |
fun future_job group (e: unit -> 'a) =
|
wenzelm@32119
|
176 |
let
|
wenzelm@35016
|
177 |
val result = Single_Assignment.var "future" : 'a result;
|
wenzelm@37053
|
178 |
val pos = Position.thread_data ();
|
wenzelm@32127
|
179 |
fun job ok =
|
wenzelm@32127
|
180 |
let
|
wenzelm@32127
|
181 |
val res =
|
wenzelm@32127
|
182 |
if ok then
|
wenzelm@32230
|
183 |
Exn.capture (fn () =>
|
wenzelm@37053
|
184 |
Multithreading.with_attributes Multithreading.private_interrupts
|
wenzelm@37053
|
185 |
(fn _ => Position.setmp_thread_data pos e ())) ()
|
wenzelm@39509
|
186 |
else Exn.interrupt_exn;
|
wenzelm@34277
|
187 |
in assign_result group result res end;
|
wenzelm@32119
|
188 |
in (result, job) end;
|
wenzelm@28156
|
189 |
|
wenzelm@34279
|
190 |
fun cancel_now group = (*requires SYNCHRONIZED*)
|
wenzelm@34280
|
191 |
Task_Queue.cancel (! queue) group;
|
wenzelm@34279
|
192 |
|
wenzelm@34279
|
193 |
fun cancel_later group = (*requires SYNCHRONIZED*)
|
wenzelm@32738
|
194 |
(Unsynchronized.change canceled (insert Task_Queue.eq_group group);
|
wenzelm@32738
|
195 |
broadcast scheduler_event);
|
wenzelm@29341
|
196 |
|
wenzelm@42563
|
197 |
fun execute (task, jobs) =
|
wenzelm@28167
|
198 |
let
|
wenzelm@42563
|
199 |
val group = Task_Queue.group_of_task task;
|
wenzelm@32122
|
200 |
val valid = not (Task_Queue.is_canceled group);
|
wenzelm@42541
|
201 |
val ok =
|
wenzelm@42541
|
202 |
Task_Queue.running task (fn () =>
|
wenzelm@42563
|
203 |
setmp_worker_task task (fn () =>
|
wenzelm@42541
|
204 |
fold (fn job => fn ok => job valid andalso ok) jobs true) ());
|
wenzelm@42541
|
205 |
val _ = Multithreading.tracing 1 (fn () =>
|
wenzelm@42541
|
206 |
let
|
wenzelm@42541
|
207 |
val s = Task_Queue.str_of_task task;
|
wenzelm@42541
|
208 |
fun micros time = string_of_int (Time.toNanoseconds time div 1000);
|
wenzelm@42560
|
209 |
val (run, wait, deps) = Task_Queue.timing_of_task task;
|
wenzelm@42560
|
210 |
in "TASK " ^ s ^ " " ^ micros run ^ " " ^ micros wait ^ " (" ^ commas deps ^ ")" end);
|
wenzelm@32250
|
211 |
val _ = SYNCHRONIZED "finish" (fn () =>
|
wenzelm@32219
|
212 |
let
|
wenzelm@32738
|
213 |
val maximal = Unsynchronized.change_result queue (Task_Queue.finish task);
|
wenzelm@32219
|
214 |
val _ =
|
wenzelm@32219
|
215 |
if ok then ()
|
wenzelm@34279
|
216 |
else if cancel_now group then ()
|
wenzelm@34279
|
217 |
else cancel_later group;
|
wenzelm@32219
|
218 |
val _ = broadcast work_finished;
|
wenzelm@33434
|
219 |
val _ = if maximal then () else signal work_available;
|
wenzelm@32219
|
220 |
in () end);
|
wenzelm@28167
|
221 |
in () end;
|
wenzelm@28167
|
222 |
|
wenzelm@28167
|
223 |
|
wenzelm@28167
|
224 |
(* worker threads *)
|
wenzelm@28167
|
225 |
|
wenzelm@33431
|
226 |
fun worker_wait active cond = (*requires SYNCHRONIZED*)
|
wenzelm@33427
|
227 |
let
|
wenzelm@33431
|
228 |
val state =
|
wenzelm@33431
|
229 |
(case AList.lookup Thread.equal (! workers) (Thread.self ()) of
|
wenzelm@33431
|
230 |
SOME state => state
|
wenzelm@33431
|
231 |
| NONE => raise Fail "Unregistered worker thread");
|
wenzelm@33431
|
232 |
val _ = state := (if active then Waiting else Sleeping);
|
wenzelm@33427
|
233 |
val _ = wait cond;
|
wenzelm@33431
|
234 |
val _ = state := Working;
|
wenzelm@33427
|
235 |
in () end;
|
wenzelm@28162
|
236 |
|
wenzelm@33436
|
237 |
fun worker_next () = (*requires SYNCHRONIZED*)
|
wenzelm@33427
|
238 |
if length (! workers) > ! max_workers then
|
wenzelm@33427
|
239 |
(Unsynchronized.change workers (AList.delete Thread.equal (Thread.self ()));
|
wenzelm@33436
|
240 |
signal work_available;
|
wenzelm@28167
|
241 |
NONE)
|
wenzelm@33431
|
242 |
else if count_workers Working > ! max_active then
|
wenzelm@33436
|
243 |
(worker_wait false work_available; worker_next ())
|
wenzelm@28166
|
244 |
else
|
wenzelm@32738
|
245 |
(case Unsynchronized.change_result queue (Task_Queue.dequeue (Thread.self ())) of
|
wenzelm@33436
|
246 |
NONE => (worker_wait false work_available; worker_next ())
|
wenzelm@33434
|
247 |
| some => (signal work_available; some));
|
wenzelm@28156
|
248 |
|
wenzelm@28167
|
249 |
fun worker_loop name =
|
wenzelm@33436
|
250 |
(case SYNCHRONIZED name (fn () => worker_next ()) of
|
wenzelm@29120
|
251 |
NONE => ()
|
wenzelm@33429
|
252 |
| SOME work => (execute work; worker_loop name));
|
wenzelm@28156
|
253 |
|
wenzelm@33428
|
254 |
fun worker_start name = (*requires SYNCHRONIZED*)
|
wenzelm@37216
|
255 |
Unsynchronized.change workers (cons (Simple_Thread.fork false (fn () => worker_loop name),
|
wenzelm@33431
|
256 |
Unsynchronized.ref Working));
|
wenzelm@28156
|
257 |
|
wenzelm@28156
|
258 |
|
wenzelm@28156
|
259 |
(* scheduler *)
|
wenzelm@28156
|
260 |
|
wenzelm@33428
|
261 |
val status_ticks = Unsynchronized.ref 0;
|
wenzelm@33428
|
262 |
|
wenzelm@33428
|
263 |
val last_round = Unsynchronized.ref Time.zeroTime;
|
wenzelm@40553
|
264 |
val next_round = seconds 0.05;
|
wenzelm@32226
|
265 |
|
wenzelm@28206
|
266 |
fun scheduler_next () = (*requires SYNCHRONIZED*)
|
wenzelm@28156
|
267 |
let
|
wenzelm@33428
|
268 |
val now = Time.now ();
|
wenzelm@33428
|
269 |
val tick = Time.<= (Time.+ (! last_round, next_round), now);
|
wenzelm@33428
|
270 |
val _ = if tick then last_round := now else ();
|
wenzelm@33428
|
271 |
|
wenzelm@33436
|
272 |
|
wenzelm@33436
|
273 |
(* queue and worker status *)
|
wenzelm@33436
|
274 |
|
wenzelm@32226
|
275 |
val _ =
|
wenzelm@33428
|
276 |
if tick then Unsynchronized.change status_ticks (fn i => (i + 1) mod 10) else ();
|
wenzelm@33428
|
277 |
val _ =
|
wenzelm@33428
|
278 |
if tick andalso ! status_ticks = 0 then
|
wenzelm@33428
|
279 |
Multithreading.tracing 1 (fn () =>
|
wenzelm@33428
|
280 |
let
|
wenzelm@34277
|
281 |
val {ready, pending, running, passive} = Task_Queue.status (! queue);
|
wenzelm@33428
|
282 |
val total = length (! workers);
|
wenzelm@33431
|
283 |
val active = count_workers Working;
|
wenzelm@33431
|
284 |
val waiting = count_workers Waiting;
|
wenzelm@33428
|
285 |
in
|
wenzelm@33428
|
286 |
"SCHEDULE " ^ Time.toString now ^ ": " ^
|
wenzelm@33428
|
287 |
string_of_int ready ^ " ready, " ^
|
wenzelm@33428
|
288 |
string_of_int pending ^ " pending, " ^
|
wenzelm@34277
|
289 |
string_of_int running ^ " running, " ^
|
wenzelm@34277
|
290 |
string_of_int passive ^ " passive; " ^
|
wenzelm@33428
|
291 |
string_of_int total ^ " workers, " ^
|
wenzelm@33431
|
292 |
string_of_int active ^ " active, " ^
|
wenzelm@33431
|
293 |
string_of_int waiting ^ " waiting "
|
wenzelm@33428
|
294 |
end)
|
wenzelm@33428
|
295 |
else ();
|
wenzelm@32053
|
296 |
|
wenzelm@28191
|
297 |
val _ =
|
wenzelm@32219
|
298 |
if forall (Thread.isActive o #1) (! workers) then ()
|
wenzelm@32115
|
299 |
else
|
wenzelm@33430
|
300 |
let
|
wenzelm@37698
|
301 |
val (alive, dead) = List.partition (Thread.isActive o #1) (! workers);
|
wenzelm@33430
|
302 |
val _ = workers := alive;
|
wenzelm@33430
|
303 |
in
|
wenzelm@33430
|
304 |
Multithreading.tracing 0 (fn () =>
|
wenzelm@33430
|
305 |
"SCHEDULE: disposed " ^ string_of_int (length dead) ^ " dead worker threads")
|
wenzelm@33430
|
306 |
end;
|
wenzelm@28191
|
307 |
|
wenzelm@33436
|
308 |
|
wenzelm@33436
|
309 |
(* worker pool adjustments *)
|
wenzelm@33436
|
310 |
|
wenzelm@33436
|
311 |
val max_active0 = ! max_active;
|
wenzelm@33436
|
312 |
val max_workers0 = ! max_workers;
|
wenzelm@33436
|
313 |
|
wenzelm@28206
|
314 |
val m = if ! do_shutdown then 0 else Multithreading.max_threads_value ();
|
wenzelm@33427
|
315 |
val _ = max_active := m;
|
wenzelm@33427
|
316 |
|
wenzelm@33432
|
317 |
val mm =
|
wenzelm@33432
|
318 |
if ! do_shutdown then 0
|
wenzelm@33432
|
319 |
else if m = 9999 then 1
|
wenzelm@33434
|
320 |
else Int.min (Int.max (count_workers Working + 2 * count_workers Waiting, m), 4 * m);
|
wenzelm@33432
|
321 |
val _ =
|
wenzelm@33432
|
322 |
if tick andalso mm > ! max_workers then
|
wenzelm@33432
|
323 |
Unsynchronized.change worker_trend (fn w => if w < 0 then 0 else w + 1)
|
wenzelm@33432
|
324 |
else if tick andalso mm < ! max_workers then
|
wenzelm@33432
|
325 |
Unsynchronized.change worker_trend (fn w => if w > 0 then 0 else w - 1)
|
wenzelm@33432
|
326 |
else ();
|
wenzelm@33432
|
327 |
val _ =
|
wenzelm@33436
|
328 |
if mm = 0 orelse ! worker_trend > 50 orelse ! worker_trend < ~50 then
|
wenzelm@33436
|
329 |
max_workers := mm
|
wenzelm@33436
|
330 |
else if ! worker_trend > 5 andalso ! max_workers < 2 * m then
|
wenzelm@33436
|
331 |
max_workers := Int.min (mm, 2 * m)
|
wenzelm@33432
|
332 |
else ();
|
wenzelm@33427
|
333 |
|
wenzelm@33428
|
334 |
val missing = ! max_workers - length (! workers);
|
wenzelm@28203
|
335 |
val _ =
|
wenzelm@33428
|
336 |
if missing > 0 then
|
wenzelm@33436
|
337 |
funpow missing (fn () =>
|
wenzelm@33436
|
338 |
ignore (worker_start ("worker " ^ string_of_int (Unsynchronized.inc next)))) ()
|
wenzelm@28203
|
339 |
else ();
|
wenzelm@28206
|
340 |
|
wenzelm@33436
|
341 |
val _ =
|
wenzelm@33436
|
342 |
if ! max_active = max_active0 andalso ! max_workers = max_workers0 then ()
|
wenzelm@33436
|
343 |
else signal work_available;
|
wenzelm@33436
|
344 |
|
wenzelm@33436
|
345 |
|
wenzelm@33436
|
346 |
(* canceled groups *)
|
wenzelm@33436
|
347 |
|
wenzelm@32225
|
348 |
val _ =
|
wenzelm@32225
|
349 |
if null (! canceled) then ()
|
wenzelm@32293
|
350 |
else
|
wenzelm@32293
|
351 |
(Multithreading.tracing 1 (fn () =>
|
wenzelm@32293
|
352 |
string_of_int (length (! canceled)) ^ " canceled groups");
|
wenzelm@34279
|
353 |
Unsynchronized.change canceled (filter_out cancel_now);
|
wenzelm@32293
|
354 |
broadcast_work ());
|
wenzelm@28206
|
355 |
|
wenzelm@33436
|
356 |
|
wenzelm@33436
|
357 |
(* delay loop *)
|
wenzelm@33436
|
358 |
|
wenzelm@32298
|
359 |
val _ = Exn.release (wait_timeout next_round scheduler_event);
|
wenzelm@32219
|
360 |
|
wenzelm@33436
|
361 |
|
wenzelm@33436
|
362 |
(* shutdown *)
|
wenzelm@33436
|
363 |
|
wenzelm@34277
|
364 |
val _ = if Task_Queue.all_passive (! queue) then do_shutdown := true else ();
|
wenzelm@32219
|
365 |
val continue = not (! do_shutdown andalso null (! workers));
|
wenzelm@28206
|
366 |
val _ = if continue then () else scheduler := NONE;
|
wenzelm@33436
|
367 |
|
wenzelm@32219
|
368 |
val _ = broadcast scheduler_event;
|
wenzelm@32298
|
369 |
in continue end
|
wenzelm@39509
|
370 |
handle exn =>
|
wenzelm@39509
|
371 |
if Exn.is_interrupt exn then
|
wenzelm@39509
|
372 |
(Multithreading.tracing 1 (fn () => "Interrupt");
|
wenzelm@39509
|
373 |
List.app cancel_later (Task_Queue.cancel_all (! queue));
|
wenzelm@39509
|
374 |
broadcast_work (); true)
|
wenzelm@39509
|
375 |
else reraise exn;
|
wenzelm@32298
|
376 |
|
wenzelm@28206
|
377 |
fun scheduler_loop () =
|
wenzelm@33437
|
378 |
while
|
wenzelm@33437
|
379 |
Multithreading.with_attributes
|
wenzelm@33437
|
380 |
(Multithreading.sync_interrupts Multithreading.public_interrupts)
|
wenzelm@33437
|
381 |
(fn _ => SYNCHRONIZED "scheduler" (fn () => scheduler_next ()))
|
wenzelm@33437
|
382 |
do ();
|
wenzelm@28191
|
383 |
|
wenzelm@28203
|
384 |
fun scheduler_active () = (*requires SYNCHRONIZED*)
|
wenzelm@28203
|
385 |
(case ! scheduler of NONE => false | SOME thread => Thread.isActive thread);
|
wenzelm@28203
|
386 |
|
wenzelm@32228
|
387 |
fun scheduler_check () = (*requires SYNCHRONIZED*)
|
wenzelm@32228
|
388 |
(do_shutdown := false;
|
wenzelm@32252
|
389 |
if scheduler_active () then ()
|
wenzelm@37216
|
390 |
else scheduler := SOME (Simple_Thread.fork false scheduler_loop));
|
wenzelm@28191
|
391 |
|
wenzelm@28191
|
392 |
|
wenzelm@28191
|
393 |
|
wenzelm@29370
|
394 |
(** futures **)
|
wenzelm@29370
|
395 |
|
wenzelm@29370
|
396 |
(* fork *)
|
wenzelm@29370
|
397 |
|
wenzelm@42545
|
398 |
fun forks {name, group, deps, pri} es =
|
wenzelm@42545
|
399 |
if null es then []
|
wenzelm@42545
|
400 |
else
|
wenzelm@42545
|
401 |
let
|
wenzelm@42545
|
402 |
val grp =
|
wenzelm@42545
|
403 |
(case group of
|
wenzelm@42545
|
404 |
NONE => worker_subgroup ()
|
wenzelm@42545
|
405 |
| SOME grp => grp);
|
wenzelm@42545
|
406 |
fun enqueue e (minimal, queue) =
|
wenzelm@42545
|
407 |
let
|
wenzelm@42545
|
408 |
val (result, job) = future_job grp e;
|
wenzelm@42545
|
409 |
val ((task, minimal'), queue') = Task_Queue.enqueue name grp deps pri job queue;
|
wenzelm@42563
|
410 |
val future = Future {promised = false, task = task, result = result};
|
wenzelm@42545
|
411 |
in (future, (minimal orelse minimal', queue')) end;
|
wenzelm@42545
|
412 |
in
|
wenzelm@42545
|
413 |
SYNCHRONIZED "enqueue" (fn () =>
|
wenzelm@42545
|
414 |
let
|
wenzelm@42545
|
415 |
val (futures, minimal) =
|
wenzelm@42545
|
416 |
Unsynchronized.change_result queue (fn q =>
|
wenzelm@42545
|
417 |
let val (futures, (minimal, q')) = fold_map enqueue es (false, q)
|
wenzelm@42545
|
418 |
in ((futures, minimal), q') end);
|
wenzelm@42545
|
419 |
val _ = if minimal then signal work_available else ();
|
wenzelm@42545
|
420 |
val _ = scheduler_check ();
|
wenzelm@42545
|
421 |
in futures end)
|
wenzelm@42545
|
422 |
end;
|
wenzelm@28162
|
423 |
|
wenzelm@42545
|
424 |
fun fork_pri pri e = singleton (forks {name = "", group = NONE, deps = [], pri = pri}) e;
|
wenzelm@42543
|
425 |
fun fork e = fork_pri 0 e;
|
wenzelm@28162
|
426 |
|
wenzelm@28186
|
427 |
|
wenzelm@29370
|
428 |
(* join *)
|
wenzelm@28186
|
429 |
|
wenzelm@29551
|
430 |
local
|
wenzelm@29551
|
431 |
|
wenzelm@32119
|
432 |
fun get_result x =
|
wenzelm@32119
|
433 |
(case peek x of
|
wenzelm@38120
|
434 |
NONE => Exn.Exn (Fail "Unfinished future")
|
wenzelm@39509
|
435 |
| SOME res =>
|
wenzelm@39509
|
436 |
if Exn.is_interrupt_exn res then
|
wenzelm@42563
|
437 |
(case Exn.flatten_list (Task_Queue.group_status (Task_Queue.group_of_task (task_of x))) of
|
wenzelm@39509
|
438 |
[] => res
|
wenzelm@39509
|
439 |
| exns => Exn.Exn (Exn.EXCEPTIONS exns))
|
wenzelm@39509
|
440 |
else res);
|
wenzelm@28177
|
441 |
|
wenzelm@32115
|
442 |
fun join_next deps = (*requires SYNCHRONIZED*)
|
wenzelm@42561
|
443 |
if Task_Queue.finished_deps deps then NONE
|
wenzelm@32224
|
444 |
else
|
wenzelm@42561
|
445 |
(case Unsynchronized.change_result queue (Task_Queue.dequeue_deps (Thread.self ()) deps) of
|
wenzelm@42561
|
446 |
(NONE, deps') =>
|
wenzelm@42561
|
447 |
if Task_Queue.finished_deps deps' then NONE
|
wenzelm@42561
|
448 |
else (worker_waiting deps' (fn () => worker_wait true work_finished); join_next deps')
|
wenzelm@32224
|
449 |
| (SOME work, deps') => SOME (work, deps'));
|
wenzelm@32115
|
450 |
|
wenzelm@32823
|
451 |
fun execute_work NONE = ()
|
wenzelm@42559
|
452 |
| execute_work (SOME (work, deps')) = (worker_joining (fn () => execute work); join_work deps')
|
wenzelm@32823
|
453 |
and join_work deps =
|
wenzelm@32823
|
454 |
execute_work (SYNCHRONIZED "join" (fn () => join_next deps));
|
wenzelm@32823
|
455 |
|
wenzelm@29551
|
456 |
in
|
wenzelm@29551
|
457 |
|
wenzelm@29370
|
458 |
fun join_results xs =
|
wenzelm@42559
|
459 |
let
|
wenzelm@42559
|
460 |
val _ =
|
wenzelm@42559
|
461 |
if forall is_finished xs then ()
|
wenzelm@42559
|
462 |
else if Multithreading.self_critical () then
|
wenzelm@42559
|
463 |
error "Cannot join future values within critical section"
|
wenzelm@42563
|
464 |
else if is_some (worker_task ()) then
|
wenzelm@42561
|
465 |
join_work (Task_Queue.init_deps (map task_of xs))
|
wenzelm@42561
|
466 |
else List.app (ignore o Single_Assignment.await o result_of) xs;
|
wenzelm@42559
|
467 |
in map get_result xs end;
|
wenzelm@28186
|
468 |
|
wenzelm@29551
|
469 |
end;
|
wenzelm@29551
|
470 |
|
wenzelm@28647
|
471 |
fun join_result x = singleton join_results x;
|
wenzelm@28647
|
472 |
fun join x = Exn.release (join_result x);
|
wenzelm@28156
|
473 |
|
wenzelm@28979
|
474 |
|
wenzelm@34277
|
475 |
(* fast-path versions -- bypassing full task management *)
|
wenzelm@34277
|
476 |
|
wenzelm@34277
|
477 |
fun value (x: 'a) =
|
wenzelm@34277
|
478 |
let
|
wenzelm@42563
|
479 |
val task = Task_Queue.dummy_task ();
|
wenzelm@42563
|
480 |
val group = Task_Queue.group_of_task task;
|
wenzelm@35016
|
481 |
val result = Single_Assignment.var "value" : 'a result;
|
wenzelm@34277
|
482 |
val _ = assign_result group result (Exn.Result x);
|
wenzelm@42563
|
483 |
in Future {promised = false, task = task, result = result} end;
|
wenzelm@28191
|
484 |
|
wenzelm@29384
|
485 |
fun map_future f x =
|
wenzelm@29370
|
486 |
let
|
wenzelm@29384
|
487 |
val task = task_of x;
|
wenzelm@42563
|
488 |
val group = Task_Queue.new_group (SOME (Task_Queue.group_of_task task));
|
wenzelm@29384
|
489 |
val (result, job) = future_job group (fn () => f (join x));
|
wenzelm@29384
|
490 |
|
wenzelm@32250
|
491 |
val extended = SYNCHRONIZED "extend" (fn () =>
|
wenzelm@29370
|
492 |
(case Task_Queue.extend task job (! queue) of
|
wenzelm@29370
|
493 |
SOME queue' => (queue := queue'; true)
|
wenzelm@29370
|
494 |
| NONE => false));
|
wenzelm@29370
|
495 |
in
|
wenzelm@42563
|
496 |
if extended then Future {promised = false, task = task, result = result}
|
wenzelm@42543
|
497 |
else
|
wenzelm@42544
|
498 |
singleton
|
wenzelm@42545
|
499 |
(forks {name = "Future.map", group = SOME group,
|
wenzelm@42544
|
500 |
deps = [task], pri = Task_Queue.pri_of_task task})
|
wenzelm@42543
|
501 |
(fn () => f (join x))
|
wenzelm@29370
|
502 |
end;
|
wenzelm@29370
|
503 |
|
wenzelm@29370
|
504 |
|
wenzelm@34277
|
505 |
(* promised futures -- fulfilled by external means *)
|
wenzelm@34277
|
506 |
|
wenzelm@34277
|
507 |
fun promise_group group : 'a future =
|
wenzelm@34277
|
508 |
let
|
wenzelm@35016
|
509 |
val result = Single_Assignment.var "promise" : 'a result;
|
wenzelm@39520
|
510 |
fun abort () = assign_result group result Exn.interrupt_exn
|
wenzelm@39520
|
511 |
handle Fail _ => true
|
wenzelm@39520
|
512 |
| exn =>
|
wenzelm@39520
|
513 |
if Exn.is_interrupt exn then raise Fail "Concurrent attempt to fulfill promise"
|
wenzelm@39520
|
514 |
else reraise exn;
|
wenzelm@38122
|
515 |
val task = SYNCHRONIZED "enqueue_passive" (fn () =>
|
wenzelm@38122
|
516 |
Unsynchronized.change_result queue (Task_Queue.enqueue_passive group abort));
|
wenzelm@42563
|
517 |
in Future {promised = true, task = task, result = result} end;
|
wenzelm@34277
|
518 |
|
wenzelm@38133
|
519 |
fun promise () = promise_group (worker_subgroup ());
|
wenzelm@34277
|
520 |
|
wenzelm@42563
|
521 |
fun fulfill_result (Future {promised, task, result}) res =
|
wenzelm@39520
|
522 |
if not promised then raise Fail "Not a promised future"
|
wenzelm@39520
|
523 |
else
|
wenzelm@39520
|
524 |
let
|
wenzelm@42563
|
525 |
val group = Task_Queue.group_of_task task;
|
wenzelm@39520
|
526 |
fun job ok = assign_result group result (if ok then res else Exn.interrupt_exn);
|
wenzelm@39520
|
527 |
val _ =
|
wenzelm@39520
|
528 |
Multithreading.with_attributes Multithreading.no_interrupts (fn _ =>
|
wenzelm@39520
|
529 |
let
|
wenzelm@39520
|
530 |
val still_passive =
|
wenzelm@39520
|
531 |
SYNCHRONIZED "fulfill_result" (fn () =>
|
wenzelm@39520
|
532 |
Unsynchronized.change_result queue
|
wenzelm@39520
|
533 |
(Task_Queue.dequeue_passive (Thread.self ()) task));
|
wenzelm@42563
|
534 |
in if still_passive then execute (task, [job]) else () end);
|
wenzelm@42561
|
535 |
val _ =
|
wenzelm@42561
|
536 |
worker_waiting (Task_Queue.init_deps [task])
|
wenzelm@42561
|
537 |
(fn () => Single_Assignment.await result);
|
wenzelm@39520
|
538 |
in () end;
|
wenzelm@34277
|
539 |
|
wenzelm@34277
|
540 |
fun fulfill x res = fulfill_result x (Exn.Result res);
|
wenzelm@34277
|
541 |
|
wenzelm@34277
|
542 |
|
wenzelm@29431
|
543 |
(* cancellation *)
|
wenzelm@28202
|
544 |
|
wenzelm@30621
|
545 |
fun interruptible_task f x =
|
wenzelm@30621
|
546 |
if Multithreading.available then
|
wenzelm@30621
|
547 |
Multithreading.with_attributes
|
wenzelm@42563
|
548 |
(if is_some (worker_task ())
|
wenzelm@32298
|
549 |
then Multithreading.private_interrupts
|
wenzelm@32298
|
550 |
else Multithreading.public_interrupts)
|
wenzelm@32298
|
551 |
(fn _ => f x)
|
wenzelm@30621
|
552 |
else interruptible f x;
|
wenzelm@30621
|
553 |
|
wenzelm@32228
|
554 |
(*cancel: present and future group members will be interrupted eventually*)
|
wenzelm@38122
|
555 |
fun cancel_group group = SYNCHRONIZED "cancel" (fn () =>
|
wenzelm@38122
|
556 |
(if cancel_now group then () else cancel_later group;
|
wenzelm@38122
|
557 |
signal work_available; scheduler_check ()));
|
wenzelm@38122
|
558 |
|
wenzelm@42563
|
559 |
fun cancel x = cancel_group (Task_Queue.group_of_task (task_of x));
|
wenzelm@28206
|
560 |
|
wenzelm@29370
|
561 |
|
wenzelm@32228
|
562 |
(* shutdown *)
|
wenzelm@29370
|
563 |
|
wenzelm@28203
|
564 |
fun shutdown () =
|
wenzelm@28276
|
565 |
if Multithreading.available then
|
wenzelm@28276
|
566 |
SYNCHRONIZED "shutdown" (fn () =>
|
wenzelm@32228
|
567 |
while scheduler_active () do
|
wenzelm@34279
|
568 |
(wait scheduler_event; broadcast_work ()))
|
wenzelm@28276
|
569 |
else ();
|
wenzelm@28203
|
570 |
|
wenzelm@29370
|
571 |
|
wenzelm@38492
|
572 |
(* status markup *)
|
wenzelm@37706
|
573 |
|
wenzelm@38492
|
574 |
fun status e =
|
wenzelm@37706
|
575 |
let
|
wenzelm@40705
|
576 |
val task_props =
|
wenzelm@40705
|
577 |
(case worker_task () of
|
wenzelm@40705
|
578 |
NONE => I
|
wenzelm@40705
|
579 |
| SOME task => Markup.properties [(Markup.taskN, Task_Queue.str_of_task task)]);
|
wenzelm@40705
|
580 |
val _ = Output.status (Markup.markup (task_props Markup.forked) "");
|
wenzelm@37706
|
581 |
val x = e (); (*sic -- report "joined" only for success*)
|
wenzelm@40705
|
582 |
val _ = Output.status (Markup.markup (task_props Markup.joined) "");
|
wenzelm@37706
|
583 |
in x end;
|
wenzelm@37706
|
584 |
|
wenzelm@37706
|
585 |
|
wenzelm@29370
|
586 |
(*final declarations of this structure!*)
|
wenzelm@29370
|
587 |
val map = map_future;
|
wenzelm@29370
|
588 |
|
wenzelm@28156
|
589 |
end;
|
wenzelm@28972
|
590 |
|
wenzelm@28972
|
591 |
type 'a future = 'a Future.future;
|
wenzelm@28972
|
592 |
|