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