/*
* Copyright 2011 The Netty Project
*
* The Netty Project licenses this file to you 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 org.jboss.netty.channel.socket.nio;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.spi.SelectorProvider;
import java.util.Set;
import java.util.Map.Entry;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.jboss.netty.logging.InternalLogger;
import org.jboss.netty.logging.InternalLoggerFactory;
import org.jboss.netty.util.internal.SystemPropertyUtil;
/**
* Provides information which is specific to a NIO service provider
* implementation.
*/
final class NioProviderMetadata {
static final InternalLogger logger =
InternalLoggerFactory.getInstance(NioProviderMetadata.class);
private static final String CONSTRAINT_LEVEL_PROPERTY =
"org.jboss.netty.channel.socket.nio.constraintLevel";
private static final String OLD_CONSTRAINT_LEVEL_PROPERTY =
"java.nio.channels.spi.constraintLevel";
/**
* 0 - no need to wake up to get / set interestOps (most cases)
* 1 - no need to wake up to get interestOps, but need to wake up to set.
* 2 - need to wake up to get / set interestOps (old providers)
*/
static final int CONSTRAINT_LEVEL;
static {
int constraintLevel = -1;
// Use the system property if possible.
constraintLevel = SystemPropertyUtil.get(CONSTRAINT_LEVEL_PROPERTY, -1);
if (constraintLevel < 0 || constraintLevel > 2) {
// Try the old property.
constraintLevel = SystemPropertyUtil.get(OLD_CONSTRAINT_LEVEL_PROPERTY, -1);
if (constraintLevel < 0 || constraintLevel > 2) {
constraintLevel = -1;
} else {
logger.warn(
"System property '" +
OLD_CONSTRAINT_LEVEL_PROPERTY +
"' has been deprecated. Use '" +
CONSTRAINT_LEVEL_PROPERTY + "' instead.");
}
}
if (constraintLevel >= 0) {
logger.debug(
"Setting the NIO constraint level to: " + constraintLevel);
}
if (constraintLevel < 0) {
constraintLevel = detectConstraintLevelFromSystemProperties();
if (constraintLevel < 0) {
constraintLevel = 2;
if (logger.isDebugEnabled()) {
logger.debug(
"Couldn't determine the NIO constraint level from " +
"the system properties; using the safest level (2)");
}
} else if (constraintLevel != 0) {
if (logger.isInfoEnabled()) {
logger.info(
"Using the autodetected NIO constraint level: " +
constraintLevel +
" (Use better NIO provider for better performance)");
}
} else {
if (logger.isDebugEnabled()) {
logger.debug(
"Using the autodetected NIO constraint level: " +
constraintLevel);
}
}
}
CONSTRAINT_LEVEL = constraintLevel;
if (CONSTRAINT_LEVEL < 0 || CONSTRAINT_LEVEL > 2) {
throw new Error(
"Unexpected NIO constraint level: " +
CONSTRAINT_LEVEL + ", please report this error.");
}
}
private static int detectConstraintLevelFromSystemProperties() {
String version = SystemPropertyUtil.get("java.specification.version");
String vminfo = SystemPropertyUtil.get("java.vm.info", "");
String os = SystemPropertyUtil.get("os.name");
String vendor = SystemPropertyUtil.get("java.vm.vendor");
String provider;
try {
provider = SelectorProvider.provider().getClass().getName();
} catch (Exception e) {
// Perhaps security exception.
provider = null;
}
if (version == null || os == null || vendor == null || provider == null) {
return -1;
}
os = os.toLowerCase();
vendor = vendor.toLowerCase();
// System.out.println(version);
// System.out.println(vminfo);
// System.out.println(os);
// System.out.println(vendor);
// System.out.println(provider);
// Sun JVM
if (vendor.indexOf("sun") >= 0) {
// Linux
if (os.indexOf("linux") >= 0) {
if (provider.equals("sun.nio.ch.EPollSelectorProvider") ||
provider.equals("sun.nio.ch.PollSelectorProvider")) {
return 0;
}
// Windows
} else if (os.indexOf("windows") >= 0) {
if (provider.equals("sun.nio.ch.WindowsSelectorProvider")) {
return 0;
}
// Solaris
} else if (os.indexOf("sun") >= 0 || os.indexOf("solaris") >= 0) {
if (provider.equals("sun.nio.ch.DevPollSelectorProvider")) {
return 0;
}
}
// Apple JVM
} else if (vendor.indexOf("apple") >= 0) {
// Mac OS
if (os.indexOf("mac") >= 0 && os.indexOf("os") >= 0) {
if (provider.equals("sun.nio.ch.KQueueSelectorProvider")) {
return 0;
}
}
// IBM
} else if (vendor.indexOf("ibm") >= 0) {
// Linux or AIX
if (os.indexOf("linux") >= 0 || os.indexOf("aix") >= 0) {
if (version.equals("1.5") || version.matches("^1\\.5\\D.*$")) {
if (provider.equals("sun.nio.ch.PollSelectorProvider")) {
return 1;
}
} else if (version.equals("1.6") || version.matches("^1\\.6\\D.*$")) {
// IBM JDK 1.6 has different constraint level for different
// version. The exact version can be determined only by its
// build date.
Pattern datePattern = Pattern.compile(
"(?:^|[^0-9])(" +
"[2-9][0-9]{3}" + // year
"(?:0[1-9]|1[0-2])" + // month
"(?:0[1-9]|[12][0-9]|3[01])" + // day of month
")(?:$|[^0-9])");
Matcher dateMatcher = datePattern.matcher(vminfo);
if (dateMatcher.find()) {
long dateValue = Long.parseLong(dateMatcher.group(1));
if (dateValue < 20081105L) {
// SR0, 1, and 2
return 2;
} else {
// SR3 and later
if (provider.equals("sun.nio.ch.EPollSelectorProvider")) {
return 0;
} else if (provider.equals("sun.nio.ch.PollSelectorProvider")) {
return 1;
}
}
}
}
}
// BEA
} else if (vendor.indexOf("bea") >= 0 || vendor.indexOf("oracle") >= 0) {
// Linux
if (os.indexOf("linux") >= 0) {
if (provider.equals("sun.nio.ch.EPollSelectorProvider") ||
provider.equals("sun.nio.ch.PollSelectorProvider")) {
return 0;
}
// Windows
} else if (os.indexOf("windows") >= 0) {
if (provider.equals("sun.nio.ch.WindowsSelectorProvider")) {
return 0;
}
}
// Apache Software Foundation
} else if (vendor.indexOf("apache") >= 0) {
if (provider.equals("org.apache.harmony.nio.internal.SelectorProviderImpl")) {
return 1;
}
}
// Others (untested)
return -1;
}
private static final class ConstraintLevelAutodetector {
ConstraintLevelAutodetector() {
super();
}
int autodetect() {
final int constraintLevel;
ExecutorService executor = Executors.newCachedThreadPool();
boolean success;
long startTime;
int interestOps;
ServerSocketChannel ch = null;
SelectorLoop loop = null;
try {
// Open a channel.
ch = ServerSocketChannel.open();
// Configure the channel
try {
ch.socket().bind(new InetSocketAddress(0));
ch.configureBlocking(false);
} catch (Throwable e) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to configure a temporary socket.", e);
}
return -1;
}
// Prepare the selector loop.
try {
loop = new SelectorLoop();
} catch (Throwable e) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to open a temporary selector.", e);
}
return -1;
}
// Register the channel
try {
ch.register(loop.selector, 0);
} catch (Throwable e) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to register a temporary selector.", e);
}
return -1;
}
SelectionKey key = ch.keyFor(loop.selector);
// Start the selector loop.
executor.execute(loop);
// Level 0
success = true;
for (int i = 0; i < 10; i ++) {
// Increase the probability of calling interestOps
// while select() is running.
do {
while (!loop.selecting) {
Thread.yield();
}
// Wait a little bit more.
try {
Thread.sleep(50);
} catch (InterruptedException e) {
// Ignore
}
} while (!loop.selecting);
startTime = System.nanoTime();
key.interestOps(key.interestOps() | SelectionKey.OP_ACCEPT);
key.interestOps(key.interestOps() & ~SelectionKey.OP_ACCEPT);
if (System.nanoTime() - startTime >= 500000000L) {
success = false;
break;
}
}
if (success) {
constraintLevel = 0;
} else {
// Level 1
success = true;
for (int i = 0; i < 10; i ++) {
// Increase the probability of calling interestOps
// while select() is running.
do {
while (!loop.selecting) {
Thread.yield();
}
// Wait a little bit more.
try {
Thread.sleep(50);
} catch (InterruptedException e) {
// Ignore
}
} while (!loop.selecting);
startTime = System.nanoTime();
interestOps = key.interestOps();
synchronized (loop) {
loop.selector.wakeup();
key.interestOps(interestOps | SelectionKey.OP_ACCEPT);
key.interestOps(interestOps & ~SelectionKey.OP_ACCEPT);
}
if (System.nanoTime() - startTime >= 500000000L) {
success = false;
break;
}
}
if (success) {
constraintLevel = 1;
} else {
constraintLevel = 2;
}
}
} catch (Throwable e) {
return -1;
} finally {
if (ch != null) {
try {
ch.close();
} catch (Throwable e) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to close a temporary socket.", e);
}
}
}
if (loop != null) {
loop.done = true;
try {
executor.shutdownNow();
} catch (NullPointerException ex) {
// Some JDK throws NPE here, but shouldn't.
}
try {
for (;;) {
loop.selector.wakeup();
try {
if (executor.awaitTermination(1, TimeUnit.SECONDS)) {
break;
}
} catch (InterruptedException e) {
// Ignore
}
}
} catch (Throwable e) {
// Perhaps security exception.
}
try {
loop.selector.close();
} catch (Throwable e) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to close a temporary selector.", e);
}
}
}
}
return constraintLevel;
}
}
private static final class SelectorLoop implements Runnable {
final Selector selector;
volatile boolean done;
volatile boolean selecting; // Just an approximation
SelectorLoop() throws IOException {
selector = Selector.open();
}
public void run() {
while (!done) {
synchronized (this) {
// Guard
}
try {
selecting = true;
try {
selector.select(1000);
} finally {
selecting = false;
}
Set<SelectionKey> keys = selector.selectedKeys();
for (SelectionKey k: keys) {
k.interestOps(0);
}
keys.clear();
} catch (IOException e) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to wait for a temporary selector.", e);
}
}
}
}
}
public static void main(String[] args) throws Exception {
for (Entry<Object, Object> e: System.getProperties().entrySet()) {
System.out.println(e.getKey() + ": " + e.getValue());
}
System.out.println();
System.out.println("Hard-coded Constraint Level: " + CONSTRAINT_LEVEL);
System.out.println(
"Auto-detected Constraint Level: " +
new ConstraintLevelAutodetector().autodetect());
}
private NioProviderMetadata() {
// Unused
}
}