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7114376: Make system dictionary hashtable bucket array size configurable

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7u4 new experimental flag -XX:PredictedClassLoadedCount=#

Reviewed-by: dholmes, phh, dcubed
This commit is contained in:
Karen Kinnear 2012-01-30 23:27:30 -05:00
parent d5546e27cf
commit ce074f86c3
8 changed files with 46 additions and 36 deletions
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28
hotspot/src/share/vm/classfile/systemDictionary.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2012, 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
@ -64,6 +64,9 @@ SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
int SystemDictionary::_number_of_modifications = 0;
int SystemDictionary::_sdgeneration = 0;
const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
20201,40423,99991};
oop SystemDictionary::_system_loader_lock_obj = NULL;
@ -1178,8 +1181,8 @@ void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
klassOop SystemDictionary::find_shared_class(Symbol* class_name) {
if (shared_dictionary() != NULL) {
unsigned int d_hash = dictionary()->compute_hash(class_name, Handle());
int d_index = dictionary()->hash_to_index(d_hash);
unsigned int d_hash = shared_dictionary()->compute_hash(class_name, Handle());
int d_index = shared_dictionary()->hash_to_index(d_hash);
return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
} else {
return NULL;
@ -1750,7 +1753,21 @@ void SystemDictionary::placeholders_do(OopClosure* blk) {
placeholders()->oops_do(blk);
}
// Calculate a "good" systemdictionary size based
// on predicted or current loaded classes count
int SystemDictionary::calculate_systemdictionary_size(int classcount) {
int newsize = _old_default_sdsize;
if ((classcount > 0) && !DumpSharedSpaces) {
int desiredsize = classcount/_average_depth_goal;
for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
newsize = _primelist[++_sdgeneration]) {
if (desiredsize <= newsize) {
break;
}
}
}
return newsize;
}
bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
bool result = dictionary()->do_unloading(is_alive);
constraints()->purge_loader_constraints(is_alive);
@ -1873,7 +1890,8 @@ void SystemDictionary::initialize(TRAPS) {
// Allocate arrays
assert(dictionary() == NULL,
"SystemDictionary should only be initialized once");
_dictionary = new Dictionary(_nof_buckets);
_sdgeneration = 0;
_dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
_placeholders = new PlaceholderTable(_nof_buckets);
_number_of_modifications = 0;
_loader_constraints = new LoaderConstraintTable(_loader_constraint_size);