michael@0: // Copyright 2006-2008 the V8 project authors. All rights reserved.
michael@0: // Redistribution and use in source and binary forms, with or without
michael@0: // modification, are permitted provided that the following conditions are
michael@0: // met:
michael@0: //
michael@0: //     * Redistributions of source code must retain the above copyright
michael@0: //       notice, this list of conditions and the following disclaimer.
michael@0: //     * Redistributions in binary form must reproduce the above
michael@0: //       copyright notice, this list of conditions and the following
michael@0: //       disclaimer in the documentation and/or other materials provided
michael@0: //       with the distribution.
michael@0: //     * Neither the name of Google Inc. nor the names of its
michael@0: //       contributors may be used to endorse or promote products derived
michael@0: //       from this software without specific prior written permission.
michael@0: //
michael@0: // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0: // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0: // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0: // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
michael@0: // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@0: // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@0: // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0: // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0: // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0: // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0: // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0: 
michael@0: 
michael@0: // This is a JavaScript implementation of the Richards
michael@0: // benchmark from:
michael@0: //
michael@0: //    http://www.cl.cam.ac.uk/~mr10/Bench.html
michael@0: //
michael@0: // The benchmark was originally implemented in BCPL by
michael@0: // Martin Richards.
michael@0: 
michael@0: 
michael@0: var Richards = new BenchmarkSuite('Richards', 35302, [
michael@0:   new Benchmark("Richards", runRichards)
michael@0: ]);
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * The Richards benchmark simulates the task dispatcher of an
michael@0:  * operating system.
michael@0:  **/
michael@0: function runRichards() {
michael@0:   var scheduler = new Scheduler();
michael@0:   scheduler.addIdleTask(ID_IDLE, 0, null, COUNT);
michael@0: 
michael@0:   var queue = new Packet(null, ID_WORKER, KIND_WORK);
michael@0:   queue = new Packet(queue,  ID_WORKER, KIND_WORK);
michael@0:   scheduler.addWorkerTask(ID_WORKER, 1000, queue);
michael@0: 
michael@0:   queue = new Packet(null, ID_DEVICE_A, KIND_DEVICE);
michael@0:   queue = new Packet(queue,  ID_DEVICE_A, KIND_DEVICE);
michael@0:   queue = new Packet(queue,  ID_DEVICE_A, KIND_DEVICE);
michael@0:   scheduler.addHandlerTask(ID_HANDLER_A, 2000, queue);
michael@0: 
michael@0:   queue = new Packet(null, ID_DEVICE_B, KIND_DEVICE);
michael@0:   queue = new Packet(queue,  ID_DEVICE_B, KIND_DEVICE);
michael@0:   queue = new Packet(queue,  ID_DEVICE_B, KIND_DEVICE);
michael@0:   scheduler.addHandlerTask(ID_HANDLER_B, 3000, queue);
michael@0: 
michael@0:   scheduler.addDeviceTask(ID_DEVICE_A, 4000, null);
michael@0: 
michael@0:   scheduler.addDeviceTask(ID_DEVICE_B, 5000, null);
michael@0: 
michael@0:   scheduler.schedule();
michael@0: 
michael@0:   if (scheduler.queueCount != EXPECTED_QUEUE_COUNT ||
michael@0:       scheduler.holdCount != EXPECTED_HOLD_COUNT) {
michael@0:     var msg =
michael@0:         "Error during execution: queueCount = " + scheduler.queueCount +
michael@0:         ", holdCount = " + scheduler.holdCount + ".";
michael@0:     throw new Error(msg);
michael@0:   }
michael@0: }
michael@0: 
michael@0: var COUNT = 1000;
michael@0: 
michael@0: /**
michael@0:  * These two constants specify how many times a packet is queued and
michael@0:  * how many times a task is put on hold in a correct run of richards.
michael@0:  * They don't have any meaning a such but are characteristic of a
michael@0:  * correct run so if the actual queue or hold count is different from
michael@0:  * the expected there must be a bug in the implementation.
michael@0:  **/
michael@0: var EXPECTED_QUEUE_COUNT = 2322;
michael@0: var EXPECTED_HOLD_COUNT = 928;
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * A scheduler can be used to schedule a set of tasks based on their relative
michael@0:  * priorities.  Scheduling is done by maintaining a list of task control blocks
michael@0:  * which holds tasks and the data queue they are processing.
michael@0:  * @constructor
michael@0:  */
michael@0: function Scheduler() {
michael@0:   this.queueCount = 0;
michael@0:   this.holdCount = 0;
michael@0:   this.blocks = new Array(NUMBER_OF_IDS);
michael@0:   this.list = null;
michael@0:   this.currentTcb = null;
michael@0:   this.currentId = null;
michael@0: }
michael@0: 
michael@0: var ID_IDLE       = 0;
michael@0: var ID_WORKER     = 1;
michael@0: var ID_HANDLER_A  = 2;
michael@0: var ID_HANDLER_B  = 3;
michael@0: var ID_DEVICE_A   = 4;
michael@0: var ID_DEVICE_B   = 5;
michael@0: var NUMBER_OF_IDS = 6;
michael@0: 
michael@0: var KIND_DEVICE   = 0;
michael@0: var KIND_WORK     = 1;
michael@0: 
michael@0: /**
michael@0:  * Add an idle task to this scheduler.
michael@0:  * @param {int} id the identity of the task
michael@0:  * @param {int} priority the task's priority
michael@0:  * @param {Packet} queue the queue of work to be processed by the task
michael@0:  * @param {int} count the number of times to schedule the task
michael@0:  */
michael@0: Scheduler.prototype.addIdleTask = function (id, priority, queue, count) {
michael@0:   this.addRunningTask(id, priority, queue, new IdleTask(this, 1, count));
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Add a work task to this scheduler.
michael@0:  * @param {int} id the identity of the task
michael@0:  * @param {int} priority the task's priority
michael@0:  * @param {Packet} queue the queue of work to be processed by the task
michael@0:  */
michael@0: Scheduler.prototype.addWorkerTask = function (id, priority, queue) {
michael@0:   this.addTask(id, priority, queue, new WorkerTask(this, ID_HANDLER_A, 0));
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Add a handler task to this scheduler.
michael@0:  * @param {int} id the identity of the task
michael@0:  * @param {int} priority the task's priority
michael@0:  * @param {Packet} queue the queue of work to be processed by the task
michael@0:  */
michael@0: Scheduler.prototype.addHandlerTask = function (id, priority, queue) {
michael@0:   this.addTask(id, priority, queue, new HandlerTask(this));
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Add a handler task to this scheduler.
michael@0:  * @param {int} id the identity of the task
michael@0:  * @param {int} priority the task's priority
michael@0:  * @param {Packet} queue the queue of work to be processed by the task
michael@0:  */
michael@0: Scheduler.prototype.addDeviceTask = function (id, priority, queue) {
michael@0:   this.addTask(id, priority, queue, new DeviceTask(this))
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Add the specified task and mark it as running.
michael@0:  * @param {int} id the identity of the task
michael@0:  * @param {int} priority the task's priority
michael@0:  * @param {Packet} queue the queue of work to be processed by the task
michael@0:  * @param {Task} task the task to add
michael@0:  */
michael@0: Scheduler.prototype.addRunningTask = function (id, priority, queue, task) {
michael@0:   this.addTask(id, priority, queue, task);
michael@0:   this.currentTcb.setRunning();
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Add the specified task to this scheduler.
michael@0:  * @param {int} id the identity of the task
michael@0:  * @param {int} priority the task's priority
michael@0:  * @param {Packet} queue the queue of work to be processed by the task
michael@0:  * @param {Task} task the task to add
michael@0:  */
michael@0: Scheduler.prototype.addTask = function (id, priority, queue, task) {
michael@0:   this.currentTcb = new TaskControlBlock(this.list, id, priority, queue, task);
michael@0:   this.list = this.currentTcb;
michael@0:   this.blocks[id] = this.currentTcb;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Execute the tasks managed by this scheduler.
michael@0:  */
michael@0: Scheduler.prototype.schedule = function () {
michael@0:   this.currentTcb = this.list;
michael@0:   while (this.currentTcb != null) {
michael@0:     if (this.currentTcb.isHeldOrSuspended()) {
michael@0:       this.currentTcb = this.currentTcb.link;
michael@0:     } else {
michael@0:       this.currentId = this.currentTcb.id;
michael@0:       this.currentTcb = this.currentTcb.run();
michael@0:     }
michael@0:   }
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Release a task that is currently blocked and return the next block to run.
michael@0:  * @param {int} id the id of the task to suspend
michael@0:  */
michael@0: Scheduler.prototype.release = function (id) {
michael@0:   var tcb = this.blocks[id];
michael@0:   if (tcb == null) return tcb;
michael@0:   tcb.markAsNotHeld();
michael@0:   if (tcb.priority > this.currentTcb.priority) {
michael@0:     return tcb;
michael@0:   } else {
michael@0:     return this.currentTcb;
michael@0:   }
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Block the currently executing task and return the next task control block
michael@0:  * to run.  The blocked task will not be made runnable until it is explicitly
michael@0:  * released, even if new work is added to it.
michael@0:  */
michael@0: Scheduler.prototype.holdCurrent = function () {
michael@0:   this.holdCount++;
michael@0:   this.currentTcb.markAsHeld();
michael@0:   return this.currentTcb.link;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Suspend the currently executing task and return the next task control block
michael@0:  * to run.  If new work is added to the suspended task it will be made runnable.
michael@0:  */
michael@0: Scheduler.prototype.suspendCurrent = function () {
michael@0:   this.currentTcb.markAsSuspended();
michael@0:   return this.currentTcb;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Add the specified packet to the end of the worklist used by the task
michael@0:  * associated with the packet and make the task runnable if it is currently
michael@0:  * suspended.
michael@0:  * @param {Packet} packet the packet to add
michael@0:  */
michael@0: Scheduler.prototype.queue = function (packet) {
michael@0:   var t = this.blocks[packet.id];
michael@0:   if (t == null) return t;
michael@0:   this.queueCount++;
michael@0:   packet.link = null;
michael@0:   packet.id = this.currentId;
michael@0:   return t.checkPriorityAdd(this.currentTcb, packet);
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * A task control block manages a task and the queue of work packages associated
michael@0:  * with it.
michael@0:  * @param {TaskControlBlock} link the preceding block in the linked block list
michael@0:  * @param {int} id the id of this block
michael@0:  * @param {int} priority the priority of this block
michael@0:  * @param {Packet} queue the queue of packages to be processed by the task
michael@0:  * @param {Task} task the task
michael@0:  * @constructor
michael@0:  */
michael@0: function TaskControlBlock(link, id, priority, queue, task) {
michael@0:   this.link = link;
michael@0:   this.id = id;
michael@0:   this.priority = priority;
michael@0:   this.queue = queue;
michael@0:   this.task = task;
michael@0:   if (queue == null) {
michael@0:     this.state = STATE_SUSPENDED;
michael@0:   } else {
michael@0:     this.state = STATE_SUSPENDED_RUNNABLE;
michael@0:   }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * The task is running and is currently scheduled.
michael@0:  */
michael@0: var STATE_RUNNING = 0;
michael@0: 
michael@0: /**
michael@0:  * The task has packets left to process.
michael@0:  */
michael@0: var STATE_RUNNABLE = 1;
michael@0: 
michael@0: /**
michael@0:  * The task is not currently running.  The task is not blocked as such and may
michael@0: * be started by the scheduler.
michael@0:  */
michael@0: var STATE_SUSPENDED = 2;
michael@0: 
michael@0: /**
michael@0:  * The task is blocked and cannot be run until it is explicitly released.
michael@0:  */
michael@0: var STATE_HELD = 4;
michael@0: 
michael@0: var STATE_SUSPENDED_RUNNABLE = STATE_SUSPENDED | STATE_RUNNABLE;
michael@0: var STATE_NOT_HELD = ~STATE_HELD;
michael@0: 
michael@0: TaskControlBlock.prototype.setRunning = function () {
michael@0:   this.state = STATE_RUNNING;
michael@0: };
michael@0: 
michael@0: TaskControlBlock.prototype.markAsNotHeld = function () {
michael@0:   this.state = this.state & STATE_NOT_HELD;
michael@0: };
michael@0: 
michael@0: TaskControlBlock.prototype.markAsHeld = function () {
michael@0:   this.state = this.state | STATE_HELD;
michael@0: };
michael@0: 
michael@0: TaskControlBlock.prototype.isHeldOrSuspended = function () {
michael@0:   return (this.state & STATE_HELD) != 0 || (this.state == STATE_SUSPENDED);
michael@0: };
michael@0: 
michael@0: TaskControlBlock.prototype.markAsSuspended = function () {
michael@0:   this.state = this.state | STATE_SUSPENDED;
michael@0: };
michael@0: 
michael@0: TaskControlBlock.prototype.markAsRunnable = function () {
michael@0:   this.state = this.state | STATE_RUNNABLE;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Runs this task, if it is ready to be run, and returns the next task to run.
michael@0:  */
michael@0: TaskControlBlock.prototype.run = function () {
michael@0:   var packet;
michael@0:   if (this.state == STATE_SUSPENDED_RUNNABLE) {
michael@0:     packet = this.queue;
michael@0:     this.queue = packet.link;
michael@0:     if (this.queue == null) {
michael@0:       this.state = STATE_RUNNING;
michael@0:     } else {
michael@0:       this.state = STATE_RUNNABLE;
michael@0:     }
michael@0:   } else {
michael@0:     packet = null;
michael@0:   }
michael@0:   return this.task.run(packet);
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Adds a packet to the worklist of this block's task, marks this as runnable if
michael@0:  * necessary, and returns the next runnable object to run (the one
michael@0:  * with the highest priority).
michael@0:  */
michael@0: TaskControlBlock.prototype.checkPriorityAdd = function (task, packet) {
michael@0:   if (this.queue == null) {
michael@0:     this.queue = packet;
michael@0:     this.markAsRunnable();
michael@0:     if (this.priority > task.priority) return this;
michael@0:   } else {
michael@0:     this.queue = packet.addTo(this.queue);
michael@0:   }
michael@0:   return task;
michael@0: };
michael@0: 
michael@0: TaskControlBlock.prototype.toString = function () {
michael@0:   return "tcb { " + this.task + "@" + this.state + " }";
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * An idle task doesn't do any work itself but cycles control between the two
michael@0:  * device tasks.
michael@0:  * @param {Scheduler} scheduler the scheduler that manages this task
michael@0:  * @param {int} v1 a seed value that controls how the device tasks are scheduled
michael@0:  * @param {int} count the number of times this task should be scheduled
michael@0:  * @constructor
michael@0:  */
michael@0: function IdleTask(scheduler, v1, count) {
michael@0:   this.scheduler = scheduler;
michael@0:   this.v1 = v1;
michael@0:   this.count = count;
michael@0: }
michael@0: 
michael@0: IdleTask.prototype.run = function (packet) {
michael@0:   this.count--;
michael@0:   if (this.count == 0) return this.scheduler.holdCurrent();
michael@0:   if ((this.v1 & 1) == 0) {
michael@0:     this.v1 = this.v1 >> 1;
michael@0:     return this.scheduler.release(ID_DEVICE_A);
michael@0:   } else {
michael@0:     this.v1 = (this.v1 >> 1) ^ 0xD008;
michael@0:     return this.scheduler.release(ID_DEVICE_B);
michael@0:   }
michael@0: };
michael@0: 
michael@0: IdleTask.prototype.toString = function () {
michael@0:   return "IdleTask"
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * A task that suspends itself after each time it has been run to simulate
michael@0:  * waiting for data from an external device.
michael@0:  * @param {Scheduler} scheduler the scheduler that manages this task
michael@0:  * @constructor
michael@0:  */
michael@0: function DeviceTask(scheduler) {
michael@0:   this.scheduler = scheduler;
michael@0:   this.v1 = null;
michael@0: }
michael@0: 
michael@0: DeviceTask.prototype.run = function (packet) {
michael@0:   if (packet == null) {
michael@0:     if (this.v1 == null) return this.scheduler.suspendCurrent();
michael@0:     var v = this.v1;
michael@0:     this.v1 = null;
michael@0:     return this.scheduler.queue(v);
michael@0:   } else {
michael@0:     this.v1 = packet;
michael@0:     return this.scheduler.holdCurrent();
michael@0:   }
michael@0: };
michael@0: 
michael@0: DeviceTask.prototype.toString = function () {
michael@0:   return "DeviceTask";
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * A task that manipulates work packets.
michael@0:  * @param {Scheduler} scheduler the scheduler that manages this task
michael@0:  * @param {int} v1 a seed used to specify how work packets are manipulated
michael@0:  * @param {int} v2 another seed used to specify how work packets are manipulated
michael@0:  * @constructor
michael@0:  */
michael@0: function WorkerTask(scheduler, v1, v2) {
michael@0:   this.scheduler = scheduler;
michael@0:   this.v1 = v1;
michael@0:   this.v2 = v2;
michael@0: }
michael@0: 
michael@0: WorkerTask.prototype.run = function (packet) {
michael@0:   if (packet == null) {
michael@0:     return this.scheduler.suspendCurrent();
michael@0:   } else {
michael@0:     if (this.v1 == ID_HANDLER_A) {
michael@0:       this.v1 = ID_HANDLER_B;
michael@0:     } else {
michael@0:       this.v1 = ID_HANDLER_A;
michael@0:     }
michael@0:     packet.id = this.v1;
michael@0:     packet.a1 = 0;
michael@0:     for (var i = 0; i < DATA_SIZE; i++) {
michael@0:       this.v2++;
michael@0:       if (this.v2 > 26) this.v2 = 1;
michael@0:       packet.a2[i] = this.v2;
michael@0:     }
michael@0:     return this.scheduler.queue(packet);
michael@0:   }
michael@0: };
michael@0: 
michael@0: WorkerTask.prototype.toString = function () {
michael@0:   return "WorkerTask";
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * A task that manipulates work packets and then suspends itself.
michael@0:  * @param {Scheduler} scheduler the scheduler that manages this task
michael@0:  * @constructor
michael@0:  */
michael@0: function HandlerTask(scheduler) {
michael@0:   this.scheduler = scheduler;
michael@0:   this.v1 = null;
michael@0:   this.v2 = null;
michael@0: }
michael@0: 
michael@0: HandlerTask.prototype.run = function (packet) {
michael@0:   if (packet != null) {
michael@0:     if (packet.kind == KIND_WORK) {
michael@0:       this.v1 = packet.addTo(this.v1);
michael@0:     } else {
michael@0:       this.v2 = packet.addTo(this.v2);
michael@0:     }
michael@0:   }
michael@0:   if (this.v1 != null) {
michael@0:     var count = this.v1.a1;
michael@0:     var v;
michael@0:     if (count < DATA_SIZE) {
michael@0:       if (this.v2 != null) {
michael@0:         v = this.v2;
michael@0:         this.v2 = this.v2.link;
michael@0:         v.a1 = this.v1.a2[count];
michael@0:         this.v1.a1 = count + 1;
michael@0:         return this.scheduler.queue(v);
michael@0:       }
michael@0:     } else {
michael@0:       v = this.v1;
michael@0:       this.v1 = this.v1.link;
michael@0:       return this.scheduler.queue(v);
michael@0:     }
michael@0:   }
michael@0:   return this.scheduler.suspendCurrent();
michael@0: };
michael@0: 
michael@0: HandlerTask.prototype.toString = function () {
michael@0:   return "HandlerTask";
michael@0: };
michael@0: 
michael@0: /* --- *
michael@0:  * P a c k e t
michael@0:  * --- */
michael@0: 
michael@0: var DATA_SIZE = 4;
michael@0: 
michael@0: /**
michael@0:  * A simple package of data that is manipulated by the tasks.  The exact layout
michael@0:  * of the payload data carried by a packet is not importaint, and neither is the
michael@0:  * nature of the work performed on packets by the tasks.
michael@0:  *
michael@0:  * Besides carrying data, packets form linked lists and are hence used both as
michael@0:  * data and worklists.
michael@0:  * @param {Packet} link the tail of the linked list of packets
michael@0:  * @param {int} id an ID for this packet
michael@0:  * @param {int} kind the type of this packet
michael@0:  * @constructor
michael@0:  */
michael@0: function Packet(link, id, kind) {
michael@0:   this.link = link;
michael@0:   this.id = id;
michael@0:   this.kind = kind;
michael@0:   this.a1 = 0;
michael@0:   this.a2 = new Array(DATA_SIZE);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Add this packet to the end of a worklist, and return the worklist.
michael@0:  * @param {Packet} queue the worklist to add this packet to
michael@0:  */
michael@0: Packet.prototype.addTo = function (queue) {
michael@0:   this.link = null;
michael@0:   if (queue == null) return this;
michael@0:   var peek, next = queue;
michael@0:   while ((peek = next.link) != null)
michael@0:     next = peek;
michael@0:   next.link = this;
michael@0:   return queue;
michael@0: };
michael@0: 
michael@0: Packet.prototype.toString = function () {
michael@0:   return "Packet";
michael@0: };