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8349007: The jtreg test ResolvedMethodTableHash takes excessive time

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Reviewed-by: lmesnik, matsaave
This commit is contained in:
Coleen Phillimore 2025-04-09 17:43:11 +00:00
parent 5f2a604b63
commit 6352ee1a6e
2 changed files with 80 additions and 53 deletions
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8
src/hotspot/share/prims/resolvedMethodTable.cpp
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@ -175,7 +175,13 @@ oop ResolvedMethodTable::find_method(const Method* method) {
ResolvedMethodTableLookup lookup(thread, method_hash(method), method);
ResolvedMethodGet rmg(thread, method);
_local_table->get(thread, lookup, rmg);
bool rehash_warning = false;
_local_table->get(thread, lookup, rmg, &rehash_warning);
if (rehash_warning) {
// if load factor is low but we need to rehash that's a problem with the hash function.
log_info(membername, table)("Rehash warning, load factor %g", get_load_factor());
trigger_concurrent_work();
}
return rmg.get_res_oop();
}

125
test/hotspot/jtreg/runtime/MemberName/ResolvedMethodTableHash.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2020, 2025, 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
@ -25,7 +25,11 @@
* @test
* @bug 8249719
* @summary ResolvedMethodTable hash function should take method class into account
* @run main/othervm/manual -Xmx256m -XX:MaxMetaspaceSize=256m ResolvedMethodTableHash 200000
* @requires vm.flagless
* @library /test/lib
* @modules java.base/jdk.internal.misc
* java.management
* @run driver ResolvedMethodTableHash
*/
import java.lang.invoke.MethodHandle;
@ -35,34 +39,38 @@ import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
// The test generates thousands MethodHandles to the methods of the same name
// and the same signature. This should not take too long, unless Method hash
import jdk.test.lib.process.OutputAnalyzer;
import jdk.test.lib.process.ProcessTools;
// The test generates a thousand MethodHandles to the methods of the same name
// and the same signature. The rehash warning shouldn't be returned, unless Method hash
// function takes only the name and the signature as an input.
public class ResolvedMethodTableHash extends ClassLoader {
public class ResolvedMethodTableHash {
// Generate a MethodHandle for ClassName.m()
private MethodHandle generate(String className) throws ReflectiveOperationException {
byte[] buf = new byte[100];
int size = writeClass(buf, className);
Class<?> cls = defineClass(null, buf, 0, size);
return MethodHandles.publicLookup().findStatic(cls, "m", MethodType.methodType(void.class));
}
public static class ResolvedMethodTableHashTest extends ClassLoader {
// Generate a MethodHandle for ClassName.m()
private MethodHandle generate(String className) throws ReflectiveOperationException {
byte[] buf = new byte[100];
int size = writeClass(buf, className);
Class<?> cls = defineClass(null, buf, 0, size);
return MethodHandles.publicLookup().findStatic(cls, "m", MethodType.methodType(void.class));
}
private MethodHandle generateWithSameName() throws ReflectiveOperationException {
byte[] buf = new byte[100];
int size = writeClass(buf, "MH$$");
// use different classloader instances to load the classes with the same name
Class<?> cls = new ResolvedMethodTableHash().defineClass(null, buf, 0, size);
return MethodHandles.publicLookup().findStatic(cls, "m", MethodType.methodType(void.class));
}
private MethodHandle generateWithSameName() throws ReflectiveOperationException {
byte[] buf = new byte[100];
int size = writeClass(buf, "MH$$");
// use different classloader instances to load the classes with the same name
Class<?> cls = new ResolvedMethodTableHashTest().defineClass(null, buf, 0, size);
return MethodHandles.publicLookup().findStatic(cls, "m", MethodType.methodType(void.class));
}
// Produce a class file with the given name and a single method:
// public static native void m();
private int writeClass(byte[] buf, String className) {
return ByteBuffer.wrap(buf)
.putInt(0xCAFEBABE) // magic
.putInt(50) // version: 50
.putShort((short) 7) // constant_pool_count: 7
// Produce a class file with the given name and a single method:
// public static native void m();
private int writeClass(byte[] buf, String className) {
return ByteBuffer.wrap(buf)
.putInt(0xCAFEBABE) // magic
.putInt(50) // version: 50
.putShort((short) 7) // constant_pool_count: 7
.put((byte) 7).putShort((short) 2)
.put((byte) 1).putShort((short) className.length()).put(className.getBytes())
.put((byte) 7).putShort((short) 4)
@ -70,37 +78,50 @@ public class ResolvedMethodTableHash extends ClassLoader {
.put((byte) 1).putShort((short) 1).put("m".getBytes())
.put((byte) 1).putShort((short) 3).put("()V".getBytes())
.putShort((short) 0x21) // access_flags: public super
.putShort((short) 1) // this_class: #1
.putShort((short) 3) // super_class: #3
.putShort((short) 0) // interfaces_count: 0
.putShort((short) 0) // fields_count: 0
.putShort((short) 1) // methods_count: 1
.putShort((short) 1) // this_class: #1
.putShort((short) 3) // super_class: #3
.putShort((short) 0) // interfaces_count: 0
.putShort((short) 0) // fields_count: 0
.putShort((short) 1) // methods_count: 1
.putShort((short) 0x109) // access_flags: public static native
.putShort((short) 5) // name_index: #5
.putShort((short) 6) // descriptor_index: #6
.putShort((short) 0) // attributes_count: 0
.putShort((short) 0) // attributes_count: 0
.putShort((short) 5) // name_index: #5
.putShort((short) 6) // descriptor_index: #6
.putShort((short) 0) // attributes_count: 0
.putShort((short) 0) // attributes_count: 0
.position();
}
public static void main(String[] args) throws Exception {
ResolvedMethodTableHashTest generator = new ResolvedMethodTableHashTest();
List<MethodHandle> handles = new ArrayList<>();
int count = 1001;
for (int i = 0; i < count; i++) {
// prevents metaspace oom
if (i % 20 != 0) {
handles.add(generator.generate("MH$" + i));
} else {
handles.add(generator.generateWithSameName());
}
if (i % 1000 == 0) {
System.out.println("Generated " + i + " handles");
}
}
System.out.println("Test passed");
}
}
public static void main(String[] args) throws Exception {
ResolvedMethodTableHash generator = new ResolvedMethodTableHash();
List<MethodHandle> handles = new ArrayList<>();
int count = args.length > 0 ? Integer.parseInt(args[0]) : 200000;
for (int i = 0; i < count; i++) {
// prevents metaspace oom
if (i % 20 != 0) {
handles.add(generator.generate("MH$" + i));
} else {
handles.add(generator.generateWithSameName());
}
if (i % 1000 == 0) {
System.out.println("Generated " + i + " handles");
}
}
System.out.println("Test passed");
// Running the table with only 1000 entries should not provoke a needs rehash warning, unless the hash code is bad.
ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder("-Xlog:membername+table",
ResolvedMethodTableHashTest.class.getName());
OutputAnalyzer output = new OutputAnalyzer(pb.start());
output.shouldNotContain("[membername,table] Rehash warning, load factor");
output.shouldContain("Generated 1000 handles");
output.shouldHaveExitValue(0);
}
}