rx.internal.schedulers.EventLoopsScheduler Maven / Gradle / Ivy
/**
* Copyright 2014 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rx.internal.schedulers;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicReference;
import rx.*;
import rx.functions.Action0;
import rx.internal.util.*;
import rx.subscriptions.*;
public final class EventLoopsScheduler extends Scheduler implements SchedulerLifecycle {
/**
* Key to setting the maximum number of computation scheduler threads.
* Zero or less is interpreted as use available. Capped by available.
*/
static final String KEY_MAX_THREADS = "rx.scheduler.max-computation-threads";
/** The maximum number of computation scheduler threads. */
static final int MAX_THREADS;
static {
int maxThreads = Integer.getInteger(KEY_MAX_THREADS, 0);
int cpuCount = Runtime.getRuntime().availableProcessors();
int max;
if (maxThreads <= 0 || maxThreads > cpuCount) {
max = cpuCount;
} else {
max = maxThreads;
}
MAX_THREADS = max;
}
static final PoolWorker SHUTDOWN_WORKER;
static {
SHUTDOWN_WORKER = new PoolWorker(RxThreadFactory.NONE);
SHUTDOWN_WORKER.unsubscribe();
}
/** This will indicate no pool is active. */
static final FixedSchedulerPool NONE = new FixedSchedulerPool(null, 0);
final ThreadFactory threadFactory;
final AtomicReference pool;
static final class FixedSchedulerPool {
final int cores;
final PoolWorker[] eventLoops;
long n;
FixedSchedulerPool(ThreadFactory threadFactory, int maxThreads) {
// initialize event loops
this.cores = maxThreads;
this.eventLoops = new PoolWorker[maxThreads];
for (int i = 0; i < maxThreads; i++) {
this.eventLoops[i] = new PoolWorker(threadFactory);
}
}
public PoolWorker getEventLoop() {
int c = cores;
if (c == 0) {
return SHUTDOWN_WORKER;
}
// simple round robin, improvements to come
return eventLoops[(int)(n++ % c)];
}
public void shutdown() {
for (PoolWorker w : eventLoops) {
w.unsubscribe();
}
}
}
/**
* Create a scheduler with pool size equal to the available processor
* count and using least-recent worker selection policy.
* @param threadFactory the factory to use with the executors
*/
public EventLoopsScheduler(ThreadFactory threadFactory) {
this.threadFactory = threadFactory;
this.pool = new AtomicReference(NONE);
start();
}
@Override
public Worker createWorker() {
return new EventLoopWorker(pool.get().getEventLoop());
}
@Override
public void start() {
FixedSchedulerPool update = new FixedSchedulerPool(threadFactory, MAX_THREADS);
if (!pool.compareAndSet(NONE, update)) {
update.shutdown();
}
}
@Override
public void shutdown() {
for (;;) {
FixedSchedulerPool curr = pool.get();
if (curr == NONE) {
return;
}
if (pool.compareAndSet(curr, NONE)) {
curr.shutdown();
return;
}
}
}
/**
* Schedules the action directly on one of the event loop workers
* without the additional infrastructure and checking.
* @param action the action to schedule
* @return the subscription
*/
public Subscription scheduleDirect(Action0 action) {
PoolWorker pw = pool.get().getEventLoop();
return pw.scheduleActual(action, -1, TimeUnit.NANOSECONDS);
}
static final class EventLoopWorker extends Scheduler.Worker {
private final SubscriptionList serial = new SubscriptionList();
private final CompositeSubscription timed = new CompositeSubscription();
private final SubscriptionList both = new SubscriptionList(serial, timed);
private final PoolWorker poolWorker;
EventLoopWorker(PoolWorker poolWorker) {
this.poolWorker = poolWorker;
}
@Override
public void unsubscribe() {
both.unsubscribe();
}
@Override
public boolean isUnsubscribed() {
return both.isUnsubscribed();
}
@Override
public Subscription schedule(final Action0 action) {
if (isUnsubscribed()) {
return Subscriptions.unsubscribed();
}
return poolWorker.scheduleActual(new Action0() {
@Override
public void call() {
if (isUnsubscribed()) {
return;
}
action.call();
}
}, 0, null, serial);
}
@Override
public Subscription schedule(final Action0 action, long delayTime, TimeUnit unit) {
if (isUnsubscribed()) {
return Subscriptions.unsubscribed();
}
return poolWorker.scheduleActual(new Action0() {
@Override
public void call() {
if (isUnsubscribed()) {
return;
}
action.call();
}
}, delayTime, unit, timed);
}
}
static final class PoolWorker extends NewThreadWorker {
PoolWorker(ThreadFactory threadFactory) {
super(threadFactory);
}
}
}
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