Mercurial > hg > graal-compiler
view src/share/vm/utilities/hashtable.cpp @ 2149:7e37af9d69ef
7011379: G1: overly long concurrent marking cycles
Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads.
Reviewed-by: johnc, ysr
author | tonyp |
---|---|
date | Wed, 19 Jan 2011 09:35:17 -0500 |
parents | f95d63e2154a |
children | 3582bf76420e |
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/* * Copyright (c) 2003, 2010, 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. * * 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. * */ #include "precompiled.hpp" #include "memory/allocation.inline.hpp" #include "memory/resourceArea.hpp" #include "oops/oop.inline.hpp" #include "runtime/safepoint.hpp" #include "utilities/dtrace.hpp" #include "utilities/hashtable.hpp" #include "utilities/hashtable.inline.hpp" HS_DTRACE_PROBE_DECL4(hs_private, hashtable__new_entry, void*, unsigned int, oop, void*); // This is a generic hashtable, designed to be used for the symbol // and string tables. // // It is implemented as an open hash table with a fixed number of buckets. // // %note: // - HashtableEntrys are allocated in blocks to reduce the space overhead. BasicHashtableEntry* BasicHashtable::new_entry(unsigned int hashValue) { BasicHashtableEntry* entry; if (_free_list) { entry = _free_list; _free_list = _free_list->next(); } else { if (_first_free_entry + _entry_size >= _end_block) { int block_size = MIN2(512, MAX2((int)_table_size / 2, (int)_number_of_entries)); int len = _entry_size * block_size; len = 1 << log2_intptr(len); // round down to power of 2 assert(len >= _entry_size, ""); _first_free_entry = NEW_C_HEAP_ARRAY(char, len); _end_block = _first_free_entry + len; } entry = (BasicHashtableEntry*)_first_free_entry; _first_free_entry += _entry_size; } assert(_entry_size % HeapWordSize == 0, ""); entry->set_hash(hashValue); return entry; } HashtableEntry* Hashtable::new_entry(unsigned int hashValue, oop obj) { HashtableEntry* entry; entry = (HashtableEntry*)BasicHashtable::new_entry(hashValue); entry->set_literal(obj); // clears literal string field HS_DTRACE_PROBE4(hs_private, hashtable__new_entry, this, hashValue, obj, entry); return entry; } // GC support void Hashtable::unlink(BoolObjectClosure* is_alive) { // Readers of the table are unlocked, so we should only be removing // entries at a safepoint. assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); for (int i = 0; i < table_size(); ++i) { for (HashtableEntry** p = bucket_addr(i); *p != NULL; ) { HashtableEntry* entry = *p; if (entry->is_shared()) { break; } assert(entry->literal() != NULL, "just checking"); if (is_alive->do_object_b(entry->literal())) { p = entry->next_addr(); } else { *p = entry->next(); free_entry(entry); } } } } void Hashtable::oops_do(OopClosure* f) { for (int i = 0; i < table_size(); ++i) { HashtableEntry** p = bucket_addr(i); HashtableEntry* entry = bucket(i); while (entry != NULL) { f->do_oop(entry->literal_addr()); // Did the closure remove the literal from the table? if (entry->literal() == NULL) { assert(!entry->is_shared(), "immutable hashtable entry?"); *p = entry->next(); free_entry(entry); } else { p = entry->next_addr(); } entry = (HashtableEntry*)HashtableEntry::make_ptr(*p); } } } // Reverse the order of elements in the hash buckets. void BasicHashtable::reverse() { for (int i = 0; i < _table_size; ++i) { BasicHashtableEntry* new_list = NULL; BasicHashtableEntry* p = bucket(i); while (p != NULL) { BasicHashtableEntry* next = p->next(); p->set_next(new_list); new_list = p; p = next; } *bucket_addr(i) = new_list; } } // Copy the table to the shared space. void BasicHashtable::copy_table(char** top, char* end) { // Dump the hash table entries. intptr_t *plen = (intptr_t*)(*top); *top += sizeof(*plen); int i; for (i = 0; i < _table_size; ++i) { for (BasicHashtableEntry** p = _buckets[i].entry_addr(); *p != NULL; p = (*p)->next_addr()) { if (*top + entry_size() > end) { warning("\nThe shared miscellaneous data space is not large " "enough to \npreload requested classes. Use " "-XX:SharedMiscDataSize= to increase \nthe initial " "size of the miscellaneous data space.\n"); exit(2); } *p = (BasicHashtableEntry*)memcpy(*top, *p, entry_size()); *top += entry_size(); } } *plen = (char*)(*top) - (char*)plen - sizeof(*plen); // Set the shared bit. for (i = 0; i < _table_size; ++i) { for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) { p->set_shared(); } } } // Reverse the order of elements in the hash buckets. void Hashtable::reverse(void* boundary) { for (int i = 0; i < table_size(); ++i) { HashtableEntry* high_list = NULL; HashtableEntry* low_list = NULL; HashtableEntry* last_low_entry = NULL; HashtableEntry* p = bucket(i); while (p != NULL) { HashtableEntry* next = p->next(); if ((void*)p->literal() >= boundary) { p->set_next(high_list); high_list = p; } else { p->set_next(low_list); low_list = p; if (last_low_entry == NULL) { last_low_entry = p; } } p = next; } if (low_list != NULL) { *bucket_addr(i) = low_list; last_low_entry->set_next(high_list); } else { *bucket_addr(i) = high_list; } } } // Dump the hash table buckets. void BasicHashtable::copy_buckets(char** top, char* end) { intptr_t len = _table_size * sizeof(HashtableBucket); *(intptr_t*)(*top) = len; *top += sizeof(intptr_t); *(intptr_t*)(*top) = _number_of_entries; *top += sizeof(intptr_t); if (*top + len > end) { warning("\nThe shared miscellaneous data space is not large " "enough to \npreload requested classes. Use " "-XX:SharedMiscDataSize= to increase \nthe initial " "size of the miscellaneous data space.\n"); exit(2); } _buckets = (HashtableBucket*)memcpy(*top, _buckets, len); *top += len; } #ifndef PRODUCT void Hashtable::print() { ResourceMark rm; for (int i = 0; i < table_size(); i++) { HashtableEntry* entry = bucket(i); while(entry != NULL) { tty->print("%d : ", i); entry->literal()->print(); tty->cr(); entry = entry->next(); } } } void BasicHashtable::verify() { int count = 0; for (int i = 0; i < table_size(); i++) { for (BasicHashtableEntry* p = bucket(i); p != NULL; p = p->next()) { ++count; } } assert(count == number_of_entries(), "number of hashtable entries incorrect"); } #endif // PRODUCT #ifdef ASSERT void BasicHashtable::verify_lookup_length(double load) { if ((double)_lookup_length / (double)_lookup_count > load * 2.0) { warning("Performance bug: SystemDictionary lookup_count=%d " "lookup_length=%d average=%lf load=%f", _lookup_count, _lookup_length, (double) _lookup_length / _lookup_count, load); } } #endif