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Counter
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Target_com_oracle_svm_core_util_Counter
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CounterGroupList
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CounterSupport
/*
* Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.oracle.svm.core.util;
// Checkstyle: allow reflection
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.graalvm.nativeimage.ImageSingletons;
import org.graalvm.nativeimage.Platform;
import org.graalvm.nativeimage.Platforms;
import com.oracle.svm.core.annotate.Alias;
import com.oracle.svm.core.annotate.AlwaysInline;
import com.oracle.svm.core.annotate.NeverInline;
import com.oracle.svm.core.annotate.RecomputeFieldValue;
import com.oracle.svm.core.annotate.TargetClass;
import com.oracle.svm.core.annotate.Uninterruptible;
import com.oracle.svm.core.log.Log;
import com.oracle.svm.core.option.HostedOptionKey;
import com.oracle.svm.core.util.Counter.Group;
A counter that can be incremented. The counting code is only emitted when an option is enabled. Counters are grouped for printing. Currently there is no shutdown hook in Substrate VM that is invoked automatically, so logValues() needs to be called manually at the end of the application to print counter values. Use this class in the following way: @Option(help = "Count foo")//
@RuntimeOption//
public static final StableOptionValue<Boolean> FooCounters = new StableOptionValue<>(false);
private static final Counter.Group fooCounters = new Counter.Group(FooCounters, "Foo Counters");
private static final Counter fooCount = new Counter(fooCounters, "foo", "number of times foo was invoked");
void foo() {
fooCount.inc();
}
/**
* A counter that can be {@linkplain #inc() incremented}. The counting code is only emitted when an
* option is enabled. Counters are {@link Group grouped} for printing.
*
* Currently there is no shutdown hook in Substrate VM that is invoked automatically, so
* {@link Counter#logValues()} needs to be called manually at the end of the application to print
* counter values.
*
* Use this class in the following way:
*
* <pre>
* @Option(help = "Count foo")//
* @RuntimeOption//
* public static final StableOptionValue<Boolean> FooCounters = new StableOptionValue<>(false);
*
* private static final Counter.Group fooCounters = new Counter.Group(FooCounters, "Foo Counters");
* private static final Counter fooCount = new Counter(fooCounters, "foo", "number of times foo was invoked");
*
* void foo() {
* fooCount.inc();
* }
* </pre>
*/
public final class Counter {
A group of related counters.
/**
* A group of related counters.
*/
public static final class Group {
protected final String name;
protected Counter[] counters = new Counter[0];
@Platforms(Platform.HOSTED_ONLY.class)//
final HostedOptionKey<Boolean> enabledOption;
The actual enabled value, set according to the value of the enabledOption during image generation. This field must not be written at run time, otherwise constant folding in the Counter.inc() method is not possible. /**
* The actual enabled value, set according to the value of the {@link #enabledOption} during
* image generation. This field must not be written at run time, otherwise constant folding
* in the {@link Counter#inc()} method is not possible.
*/
protected boolean enabled;
@Platforms(Platform.HOSTED_ONLY.class)
public Group(HostedOptionKey<Boolean> enabledOption, String name) {
this.name = name;
this.enabledOption = enabledOption;
ImageSingletons.lookup(CounterGroupList.class).value.add(this);
}
public Counter[] getCounters() {
return counters;
}
Resets the values of all counters in this group to 0.
/**
* Resets the values of all counters in this group to 0.
*/
public void reset() {
for (Counter counter : counters) {
counter.reset();
}
}
Prints all counters of this group to the Log. /**
* Prints all counters of this group to the {@link Log}.
*/
public void logValues() {
long total = 0;
int maxNameLen = 0;
for (Counter counter : counters) {
total += counter.getValue();
maxNameLen = Math.max(counter.name.length(), maxNameLen);
}
Log.log().string("=== ").string(name).string(" ===").newline();
for (Counter counter : counters) {
long counterValue = counter.getValue();
long percent = total == 0 ? 0 : counterValue * 100 / total;
Log.log().string(" ").string(counter.name, maxNameLen, Log.RIGHT_ALIGN).string(":");
Log.log().unsigned(counterValue, 10, Log.RIGHT_ALIGN).unsigned(percent, 5, Log.RIGHT_ALIGN).string("%");
if (!counter.description.isEmpty()) {
Log.log().string(" // ").string(counter.description);
}
Log.log().newline();
}
Log.log().string(" ").string("TOTAL", maxNameLen, Log.RIGHT_ALIGN).string(":");
Log.log().unsigned(total, 10, Log.RIGHT_ALIGN).newline();
}
}
protected final Group group;
protected final String name;
protected final String description;
protected long value;
@Platforms(Platform.HOSTED_ONLY.class)//
public static final Field VALUE_FIELD;
static {
try {
VALUE_FIELD = Counter.class.getDeclaredField("value");
} catch (NoSuchFieldException ex) {
throw VMError.shouldNotReachHere(ex);
}
}
Creates a counter.
Params: - group – the group to which the counter belongs.
- name – the name of the counter
- description – a brief comment describing the metric represented by the counter
/**
* Creates a counter.
*
* @param group the group to which the counter belongs.
* @param name the name of the counter
* @param description a brief comment describing the metric represented by the counter
*/
@Platforms(Platform.HOSTED_ONLY.class)
public Counter(Group group, String name, String description) {
this.group = group;
this.name = name;
this.description = description;
group.counters = Arrays.copyOf(group.counters, group.counters.length + 1);
group.counters[group.counters.length - 1] = this;
}
Returns the value of this counter.
/**
* Returns the value of this counter.
*/
@NeverInline("Counters can be incremented in snippets, prevent wrong memory access reordering")
public long getValue() {
return value;
}
public String getName() {
return name;
}
Increments the value of this counter.
/**
* Increments the value of this counter.
*/
@AlwaysInline("Constant folding and dead code elimination remove code for disabled counters")
@Uninterruptible(reason = "Gets always inlined", mayBeInlined = true)
public void inc() {
add(1);
}
Increments the value of this counter.
/**
* Increments the value of this counter.
*/
@AlwaysInline("Constant folding and dead code elimination remove code for disabled counters")
@Uninterruptible(reason = "Gets always inlined", mayBeInlined = true)
public void add(long increment) {
if (group.enabled) {
value += increment;
}
}
Resets the value of this counter to 0.
/**
* Resets the value of this counter to 0.
*/
@NeverInline("Counters can be incremented in snippets, prevent wrong memory access reordering")
public void reset() {
value = 0;
}
Prints all counters of all enabled groups to the Log. /**
* Prints all counters of all enabled groups to the {@link Log}.
*/
public static void logValues() {
for (Counter.Group group : ImageSingletons.lookup(CounterSupport.class).enabledGroups) {
group.logValues();
}
}
}
@TargetClass(com.oracle.svm.core.util.Counter.class)
final class Target_com_oracle_svm_core_util_Counter {
/*
* Ensure that the counter value is 0 when execution starts at run time. We do not want to start
* with counter values that were incremented during image generation.
*/
@Alias//
@RecomputeFieldValue(kind = RecomputeFieldValue.Kind.Reset)//
private long value;
}
class CounterGroupList {
final List<Group> value = new ArrayList<>();
}
class CounterSupport {
final Counter.Group[] enabledGroups;
CounterSupport(Counter.Group[] enabledGroups) {
this.enabledGroups = enabledGroups;
}
}