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QuestDB is High Performance Time Series Database
/*******************************************************************************
* ___ _ ____ ____
* / _ \ _ _ ___ ___| |_| _ \| __ )
* | | | | | | |/ _ \/ __| __| | | | _ \
* | |_| | |_| | __/\__ \ |_| |_| | |_) |
* \__\_\\__,_|\___||___/\__|____/|____/
*
* Copyright (c) 2014-2019 Appsicle
* Copyright (c) 2019-2020 QuestDB
*
* 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 io.questdb.mp;
import io.questdb.log.Log;
import io.questdb.std.ObjHashSet;
import io.questdb.std.Os;
import io.questdb.std.Unsafe;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.LockSupport;
public class Worker extends Thread {
private final static long RUNNING_OFFSET = Unsafe.getFieldOffset(Worker.class, "running");
private static final long YIELD_THRESHOLD = 10L;
private static final long SLEEP_THRESHOLD = 10000L;
private final static AtomicInteger COUNTER = new AtomicInteger();
private final ObjHashSet jobs;
private final SOCountDownLatch haltLatch;
private final int affinity;
private final Log log;
private final WorkerCleaner cleaner;
private final boolean haltOnError;
private final int workerId;
private volatile int running = 0;
private volatile int fence;
public Worker(
ObjHashSet jobs,
SOCountDownLatch haltLatch,
int workerId
) {
this(jobs, haltLatch, -1, null, null, true, workerId);
}
public Worker(
final ObjHashSet jobs,
final SOCountDownLatch haltLatch,
final int affinity,
final Log log,
final WorkerCleaner cleaner,
final boolean haltOnError,
final int workerId
) {
this.log = log;
this.jobs = jobs;
this.haltLatch = haltLatch;
this.setName("questdb-worker-" + COUNTER.incrementAndGet());
this.affinity = affinity;
this.cleaner = cleaner;
this.haltOnError = haltOnError;
this.workerId = workerId;
}
public int getWorkerId() {
return workerId;
}
public void halt() {
running = 2;
}
@Override
public void run() {
Throwable ex = null;
try {
if (Unsafe.getUnsafe().compareAndSwapInt(this, RUNNING_OFFSET, 0, 1)) {
if (affinity > -1) {
if (Os.setCurrentThreadAffinity(this.affinity) == 0) {
if (log != null) {
log.info().$("affinity set [cpu=").$(affinity).$(", name=").$(getName()).$(']').$();
}
} else {
if (log != null) {
log.error().$("could not set affinity [cpu=").$(affinity).$(", name=").$(getName()).$(']').$();
}
}
} else {
if (log != null) {
log.info().$("os scheduled [name=").$(getName()).$(']').$();
}
}
setupJobs();
int n = jobs.size();
long uselessCounter = 0;
while (running == 1) {
boolean useful = false;
for (int i = 0; i < n; i++) {
loadFence();
try {
try {
useful |= jobs.get(i).run(workerId);
} catch (Throwable e) {
if (haltOnError) {
throw e;
}
if (log != null) {
log.error().$("unhandled error [job=").$(jobs.get(i).toString()).$(", ex=").$(e).$(']').$();
} else {
e.printStackTrace();
}
}
} finally {
storeFence();
}
}
if (useful) {
uselessCounter = 0;
continue;
}
uselessCounter++;
if (uselessCounter < 0) {
// deal with overflow
uselessCounter = SLEEP_THRESHOLD + 1;
}
if (uselessCounter > YIELD_THRESHOLD) {
Thread.yield();
}
if (uselessCounter > SLEEP_THRESHOLD) {
LockSupport.parkNanos(1000000);
}
}
}
} catch (Throwable e) {
ex = e;
} finally {
// cleaner will typically attempt to release
// thread-local instances
if (cleaner != null) {
cleaner.run(ex);
}
haltLatch.countDown();
}
}
@SuppressWarnings("UnusedReturnValue")
private int loadFence() {
return fence;
}
private void setupJobs() {
if (running == 1) {
for (int i = 0; i < jobs.size(); i++) {
loadFence();
try {
Job job = jobs.get(i);
if (job instanceof EagerThreadSetup) {
((EagerThreadSetup) job).setup();
}
} finally {
storeFence();
}
}
}
}
private void storeFence() {
fence = 1;
}
}