1 // Copyright 2006-2008 the V8 project authors. All rights reserved.
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3 // modification, are permitted provided that the following conditions are
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7 // notice, this list of conditions and the following disclaimer.
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29 // This is a JavaScript implementation of the Richards
32 // http://www.cl.cam.ac.uk/~mr10/Bench.html
34 // The benchmark was originally implemented in BCPL by
38 var Richards
= new BenchmarkSuite('Richards', 35302, [
39 new Benchmark("Richards", runRichards
)
44 * The Richards benchmark simulates the task dispatcher of an
47 function runRichards() {
48 var scheduler
= new Scheduler();
49 scheduler
.addIdleTask(ID_IDLE
, 0, null, COUNT
);
51 var queue
= new Packet(null, ID_WORKER
, KIND_WORK
);
52 queue
= new Packet(queue
, ID_WORKER
, KIND_WORK
);
53 scheduler
.addWorkerTask(ID_WORKER
, 1000, queue
);
55 queue
= new Packet(null, ID_DEVICE_A
, KIND_DEVICE
);
56 queue
= new Packet(queue
, ID_DEVICE_A
, KIND_DEVICE
);
57 queue
= new Packet(queue
, ID_DEVICE_A
, KIND_DEVICE
);
58 scheduler
.addHandlerTask(ID_HANDLER_A
, 2000, queue
);
60 queue
= new Packet(null, ID_DEVICE_B
, KIND_DEVICE
);
61 queue
= new Packet(queue
, ID_DEVICE_B
, KIND_DEVICE
);
62 queue
= new Packet(queue
, ID_DEVICE_B
, KIND_DEVICE
);
63 scheduler
.addHandlerTask(ID_HANDLER_B
, 3000, queue
);
65 scheduler
.addDeviceTask(ID_DEVICE_A
, 4000, null);
67 scheduler
.addDeviceTask(ID_DEVICE_B
, 5000, null);
71 if (scheduler
.queueCount
!= EXPECTED_QUEUE_COUNT
||
72 scheduler
.holdCount
!= EXPECTED_HOLD_COUNT
) {
74 "Error during execution: queueCount = " + scheduler
.queueCount
+
75 ", holdCount = " + scheduler
.holdCount
+ ".";
83 * These two constants specify how many times a packet is queued and
84 * how many times a task is put on hold in a correct run of richards.
85 * They don't have any meaning a such but are characteristic of a
86 * correct run so if the actual queue or hold count is different from
87 * the expected there must be a bug in the implementation.
89 var EXPECTED_QUEUE_COUNT
= 2322;
90 var EXPECTED_HOLD_COUNT
= 928;
94 * A scheduler can be used to schedule a set of tasks based on their relative
95 * priorities. Scheduling is done by maintaining a list of task control blocks
96 * which holds tasks and the data queue they are processing.
99 function Scheduler() {
102 this.blocks
= new Array(NUMBER_OF_IDS
);
104 this.currentTcb
= null;
105 this.currentId
= null;
110 var ID_HANDLER_A
= 2;
111 var ID_HANDLER_B
= 3;
114 var NUMBER_OF_IDS
= 6;
120 * Add an idle task to this scheduler.
121 * @param {int} id the identity of the task
122 * @param {int} priority the task's priority
123 * @param {Packet} queue the queue of work to be processed by the task
124 * @param {int} count the number of times to schedule the task
126 Scheduler
.prototype.addIdleTask = function (id
, priority
, queue
, count
) {
127 this.addRunningTask(id
, priority
, queue
, new IdleTask(this, 1, count
));
131 * Add a work task to this scheduler.
132 * @param {int} id the identity of the task
133 * @param {int} priority the task's priority
134 * @param {Packet} queue the queue of work to be processed by the task
136 Scheduler
.prototype.addWorkerTask = function (id
, priority
, queue
) {
137 this.addTask(id
, priority
, queue
, new WorkerTask(this, ID_HANDLER_A
, 0));
141 * Add a handler task to this scheduler.
142 * @param {int} id the identity of the task
143 * @param {int} priority the task's priority
144 * @param {Packet} queue the queue of work to be processed by the task
146 Scheduler
.prototype.addHandlerTask = function (id
, priority
, queue
) {
147 this.addTask(id
, priority
, queue
, new HandlerTask(this));
151 * Add a handler task to this scheduler.
152 * @param {int} id the identity of the task
153 * @param {int} priority the task's priority
154 * @param {Packet} queue the queue of work to be processed by the task
156 Scheduler
.prototype.addDeviceTask = function (id
, priority
, queue
) {
157 this.addTask(id
, priority
, queue
, new DeviceTask(this))
161 * Add the specified task and mark it as running.
162 * @param {int} id the identity of the task
163 * @param {int} priority the task's priority
164 * @param {Packet} queue the queue of work to be processed by the task
165 * @param {Task} task the task to add
167 Scheduler
.prototype.addRunningTask = function (id
, priority
, queue
, task
) {
168 this.addTask(id
, priority
, queue
, task
);
169 this.currentTcb
.setRunning();
173 * Add the specified task to this scheduler.
174 * @param {int} id the identity of the task
175 * @param {int} priority the task's priority
176 * @param {Packet} queue the queue of work to be processed by the task
177 * @param {Task} task the task to add
179 Scheduler
.prototype.addTask = function (id
, priority
, queue
, task
) {
180 this.currentTcb
= new TaskControlBlock(this.list
, id
, priority
, queue
, task
);
181 this.list
= this.currentTcb
;
182 this.blocks
[id
] = this.currentTcb
;
186 * Execute the tasks managed by this scheduler.
188 Scheduler
.prototype.schedule = function () {
189 this.currentTcb
= this.list
;
190 while (this.currentTcb
!= null) {
191 if (this.currentTcb
.isHeldOrSuspended()) {
192 this.currentTcb
= this.currentTcb
.link
;
194 this.currentId
= this.currentTcb
.id
;
195 this.currentTcb
= this.currentTcb
.run();
201 * Release a task that is currently blocked and return the next block to run.
202 * @param {int} id the id of the task to suspend
204 Scheduler
.prototype.release = function (id
) {
205 var tcb
= this.blocks
[id
];
206 if (tcb
== null) return tcb
;
208 if (tcb
.priority
> this.currentTcb
.priority
) {
211 return this.currentTcb
;
216 * Block the currently executing task and return the next task control block
217 * to run. The blocked task will not be made runnable until it is explicitly
218 * released, even if new work is added to it.
220 Scheduler
.prototype.holdCurrent = function () {
222 this.currentTcb
.markAsHeld();
223 return this.currentTcb
.link
;
227 * Suspend the currently executing task and return the next task control block
228 * to run. If new work is added to the suspended task it will be made runnable.
230 Scheduler
.prototype.suspendCurrent = function () {
231 this.currentTcb
.markAsSuspended();
232 return this.currentTcb
;
236 * Add the specified packet to the end of the worklist used by the task
237 * associated with the packet and make the task runnable if it is currently
239 * @param {Packet} packet the packet to add
241 Scheduler
.prototype.queue = function (packet
) {
242 var t
= this.blocks
[packet
.id
];
243 if (t
== null) return t
;
246 packet
.id
= this.currentId
;
247 return t
.checkPriorityAdd(this.currentTcb
, packet
);
251 * A task control block manages a task and the queue of work packages associated
253 * @param {TaskControlBlock} link the preceding block in the linked block list
254 * @param {int} id the id of this block
255 * @param {int} priority the priority of this block
256 * @param {Packet} queue the queue of packages to be processed by the task
257 * @param {Task} task the task
260 function TaskControlBlock(link
, id
, priority
, queue
, task
) {
263 this.priority
= priority
;
267 this.state
= STATE_SUSPENDED
;
269 this.state
= STATE_SUSPENDED_RUNNABLE
;
274 * The task is running and is currently scheduled.
276 var STATE_RUNNING
= 0;
279 * The task has packets left to process.
281 var STATE_RUNNABLE
= 1;
284 * The task is not currently running. The task is not blocked as such and may
285 * be started by the scheduler.
287 var STATE_SUSPENDED
= 2;
290 * The task is blocked and cannot be run until it is explicitly released.
294 var STATE_SUSPENDED_RUNNABLE
= STATE_SUSPENDED
| STATE_RUNNABLE
;
295 var STATE_NOT_HELD
= ~STATE_HELD
;
297 TaskControlBlock
.prototype.setRunning = function () {
298 this.state
= STATE_RUNNING
;
301 TaskControlBlock
.prototype.markAsNotHeld = function () {
302 this.state
= this.state
& STATE_NOT_HELD
;
305 TaskControlBlock
.prototype.markAsHeld = function () {
306 this.state
= this.state
| STATE_HELD
;
309 TaskControlBlock
.prototype.isHeldOrSuspended = function () {
310 return (this.state
& STATE_HELD
) != 0 || (this.state
== STATE_SUSPENDED
);
313 TaskControlBlock
.prototype.markAsSuspended = function () {
314 this.state
= this.state
| STATE_SUSPENDED
;
317 TaskControlBlock
.prototype.markAsRunnable = function () {
318 this.state
= this.state
| STATE_RUNNABLE
;
322 * Runs this task, if it is ready to be run, and returns the next task to run.
324 TaskControlBlock
.prototype.run = function () {
326 if (this.state
== STATE_SUSPENDED_RUNNABLE
) {
328 this.queue
= packet
.link
;
329 if (this.queue
== null) {
330 this.state
= STATE_RUNNING
;
332 this.state
= STATE_RUNNABLE
;
337 return this.task
.run(packet
);
341 * Adds a packet to the worklist of this block's task, marks this as runnable if
342 * necessary, and returns the next runnable object to run (the one
343 * with the highest priority).
345 TaskControlBlock
.prototype.checkPriorityAdd = function (task
, packet
) {
346 if (this.queue
== null) {
348 this.markAsRunnable();
349 if (this.priority
> task
.priority
) return this;
351 this.queue
= packet
.addTo(this.queue
);
356 TaskControlBlock
.prototype.toString = function () {
357 return "tcb { " + this.task
+ "@" + this.state
+ " }";
361 * An idle task doesn't do any work itself but cycles control between the two
363 * @param {Scheduler} scheduler the scheduler that manages this task
364 * @param {int} v1 a seed value that controls how the device tasks are scheduled
365 * @param {int} count the number of times this task should be scheduled
368 function IdleTask(scheduler
, v1
, count
) {
369 this.scheduler
= scheduler
;
374 IdleTask
.prototype.run = function (packet
) {
376 if (this.count
== 0) return this.scheduler
.holdCurrent();
377 if ((this.v1
& 1) == 0) {
378 this.v1
= this.v1
>> 1;
379 return this.scheduler
.release(ID_DEVICE_A
);
381 this.v1
= (this.v1
>> 1) ^ 0xD008;
382 return this.scheduler
.release(ID_DEVICE_B
);
386 IdleTask
.prototype.toString = function () {
391 * A task that suspends itself after each time it has been run to simulate
392 * waiting for data from an external device.
393 * @param {Scheduler} scheduler the scheduler that manages this task
396 function DeviceTask(scheduler
) {
397 this.scheduler
= scheduler
;
401 DeviceTask
.prototype.run = function (packet
) {
402 if (packet
== null) {
403 if (this.v1
== null) return this.scheduler
.suspendCurrent();
406 return this.scheduler
.queue(v
);
409 return this.scheduler
.holdCurrent();
413 DeviceTask
.prototype.toString = function () {
418 * A task that manipulates work packets.
419 * @param {Scheduler} scheduler the scheduler that manages this task
420 * @param {int} v1 a seed used to specify how work packets are manipulated
421 * @param {int} v2 another seed used to specify how work packets are manipulated
424 function WorkerTask(scheduler
, v1
, v2
) {
425 this.scheduler
= scheduler
;
430 WorkerTask
.prototype.run = function (packet
) {
431 if (packet
== null) {
432 return this.scheduler
.suspendCurrent();
434 if (this.v1
== ID_HANDLER_A
) {
435 this.v1
= ID_HANDLER_B
;
437 this.v1
= ID_HANDLER_A
;
441 for (var i
= 0; i
< DATA_SIZE
; i
++) {
443 if (this.v2
> 26) this.v2
= 1;
444 packet
.a2
[i
] = this.v2
;
446 return this.scheduler
.queue(packet
);
450 WorkerTask
.prototype.toString = function () {
455 * A task that manipulates work packets and then suspends itself.
456 * @param {Scheduler} scheduler the scheduler that manages this task
459 function HandlerTask(scheduler
) {
460 this.scheduler
= scheduler
;
465 HandlerTask
.prototype.run = function (packet
) {
466 if (packet
!= null) {
467 if (packet
.kind
== KIND_WORK
) {
468 this.v1
= packet
.addTo(this.v1
);
470 this.v2
= packet
.addTo(this.v2
);
473 if (this.v1
!= null) {
474 var count
= this.v1
.a1
;
476 if (count
< DATA_SIZE
) {
477 if (this.v2
!= null) {
479 this.v2
= this.v2
.link
;
480 v
.a1
= this.v1
.a2
[count
];
481 this.v1
.a1
= count
+ 1;
482 return this.scheduler
.queue(v
);
486 this.v1
= this.v1
.link
;
487 return this.scheduler
.queue(v
);
490 return this.scheduler
.suspendCurrent();
493 HandlerTask
.prototype.toString = function () {
494 return "HandlerTask";
504 * A simple package of data that is manipulated by the tasks. The exact layout
505 * of the payload data carried by a packet is not importaint, and neither is the
506 * nature of the work performed on packets by the tasks.
508 * Besides carrying data, packets form linked lists and are hence used both as
509 * data and worklists.
510 * @param {Packet} link the tail of the linked list of packets
511 * @param {int} id an ID for this packet
512 * @param {int} kind the type of this packet
515 function Packet(link
, id
, kind
) {
520 this.a2
= new Array(DATA_SIZE
);
524 * Add this packet to the end of a worklist, and return the worklist.
525 * @param {Packet} queue the worklist to add this packet to
527 Packet
.prototype.addTo = function (queue
) {
529 if (queue
== null) return this;
530 var peek
, next
= queue
;
531 while ((peek
= next
.link
) != null)
537 Packet
.prototype.toString = function () {