--- old/src/share/vm/gc_implementation/g1/g1HotCardCache.hpp 2015-05-12 11:54:25.656731167 +0200 +++ /dev/null 2015-03-18 17:10:38.111854831 +0100 @@ -1,148 +0,0 @@ -/* - * Copyright (c) 2013, 2015, 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. - * - */ - -#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP -#define SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP - -#include "gc_implementation/g1/g1_globals.hpp" -#include "gc_implementation/g1/g1CardCounts.hpp" -#include "memory/allocation.hpp" -#include "runtime/safepoint.hpp" -#include "runtime/thread.hpp" -#include "utilities/globalDefinitions.hpp" - -class DirtyCardQueue; -class G1CollectedHeap; -class G1RemSet; -class HeapRegion; - -// An evicting cache of cards that have been logged by the G1 post -// write barrier. Placing a card in the cache delays the refinement -// of the card until the card is evicted, or the cache is drained -// during the next evacuation pause. -// -// The first thing the G1 post write barrier does is to check whether -// the card containing the updated pointer is already dirty and, if -// so, skips the remaining code in the barrier. -// -// Delaying the refinement of a card will make the card fail the -// first is_dirty check in the write barrier, skipping the remainder -// of the write barrier. -// -// This can significantly reduce the overhead of the write barrier -// code, increasing throughput. - -class G1HotCardCache: public CHeapObj { - - G1CollectedHeap* _g1h; - - bool _use_cache; - - G1CardCounts _card_counts; - - ArrayAllocator _hot_cache_memory; - - // The card cache table - jbyte** _hot_cache; - - size_t _hot_cache_size; - - int _hot_cache_par_chunk_size; - - // Avoids false sharing when concurrently updating _hot_cache_idx or - // _hot_cache_par_claimed_idx. These are never updated at the same time - // thus it's not necessary to separate them as well - char _pad_before[DEFAULT_CACHE_LINE_SIZE]; - - volatile size_t _hot_cache_idx; - - volatile size_t _hot_cache_par_claimed_idx; - - char _pad_after[DEFAULT_CACHE_LINE_SIZE]; - - // The number of cached cards a thread claims when flushing the cache - static const int ClaimChunkSize = 32; - - bool default_use_cache() const { - return (G1ConcRSLogCacheSize > 0); - } - - public: - G1HotCardCache(G1CollectedHeap* g1h); - ~G1HotCardCache(); - - void initialize(G1RegionToSpaceMapper* card_counts_storage); - - bool use_cache() { return _use_cache; } - - void set_use_cache(bool b) { - _use_cache = (b ? default_use_cache() : false); - } - - // Returns the card to be refined or NULL. - // - // Increments the count for given the card. if the card is not 'hot', - // it is returned for immediate refining. Otherwise the card is - // added to the hot card cache. - // If there is enough room in the hot card cache for the card we're - // adding, NULL is returned and no further action in needed. - // If we evict a card from the cache to make room for the new card, - // the evicted card is then returned for refinement. - jbyte* insert(jbyte* card_ptr); - - // Refine the cards that have delayed as a result of - // being in the cache. - void drain(uint worker_i, G1RemSet* g1rs, DirtyCardQueue* into_cset_dcq); - - // Set up for parallel processing of the cards in the hot cache - void reset_hot_cache_claimed_index() { - _hot_cache_par_claimed_idx = 0; - } - - // Resets the hot card cache and discards the entries. - void reset_hot_cache() { - assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint"); - assert(Thread::current_noinline()->is_VM_thread(), "Current thread should be the VMthread"); - if (default_use_cache()) { - reset_hot_cache_internal(); - } - } - - // Zeros the values in the card counts table for entire committed heap - void reset_card_counts(); - - // Zeros the values in the card counts table for the given region - void reset_card_counts(HeapRegion* hr); - - private: - void reset_hot_cache_internal() { - assert(_hot_cache != NULL, "Logic"); - _hot_cache_idx = 0; - for (size_t i = 0; i < _hot_cache_size; i++) { - _hot_cache[i] = NULL; - } - } -}; - -#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP --- /dev/null 2015-03-18 17:10:38.111854831 +0100 +++ new/src/share/vm/gc/g1/g1HotCardCache.hpp 2015-05-12 11:54:25.410720883 +0200 @@ -0,0 +1,148 @@ +/* + * Copyright (c) 2013, 2015, 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. + * + */ + +#ifndef SHARE_VM_GC_G1_G1HOTCARDCACHE_HPP +#define SHARE_VM_GC_G1_G1HOTCARDCACHE_HPP + +#include "gc/g1/g1CardCounts.hpp" +#include "gc/g1/g1_globals.hpp" +#include "memory/allocation.hpp" +#include "runtime/safepoint.hpp" +#include "runtime/thread.hpp" +#include "utilities/globalDefinitions.hpp" + +class DirtyCardQueue; +class G1CollectedHeap; +class G1RemSet; +class HeapRegion; + +// An evicting cache of cards that have been logged by the G1 post +// write barrier. Placing a card in the cache delays the refinement +// of the card until the card is evicted, or the cache is drained +// during the next evacuation pause. +// +// The first thing the G1 post write barrier does is to check whether +// the card containing the updated pointer is already dirty and, if +// so, skips the remaining code in the barrier. +// +// Delaying the refinement of a card will make the card fail the +// first is_dirty check in the write barrier, skipping the remainder +// of the write barrier. +// +// This can significantly reduce the overhead of the write barrier +// code, increasing throughput. + +class G1HotCardCache: public CHeapObj { + + G1CollectedHeap* _g1h; + + bool _use_cache; + + G1CardCounts _card_counts; + + ArrayAllocator _hot_cache_memory; + + // The card cache table + jbyte** _hot_cache; + + size_t _hot_cache_size; + + int _hot_cache_par_chunk_size; + + // Avoids false sharing when concurrently updating _hot_cache_idx or + // _hot_cache_par_claimed_idx. These are never updated at the same time + // thus it's not necessary to separate them as well + char _pad_before[DEFAULT_CACHE_LINE_SIZE]; + + volatile size_t _hot_cache_idx; + + volatile size_t _hot_cache_par_claimed_idx; + + char _pad_after[DEFAULT_CACHE_LINE_SIZE]; + + // The number of cached cards a thread claims when flushing the cache + static const int ClaimChunkSize = 32; + + bool default_use_cache() const { + return (G1ConcRSLogCacheSize > 0); + } + + public: + G1HotCardCache(G1CollectedHeap* g1h); + ~G1HotCardCache(); + + void initialize(G1RegionToSpaceMapper* card_counts_storage); + + bool use_cache() { return _use_cache; } + + void set_use_cache(bool b) { + _use_cache = (b ? default_use_cache() : false); + } + + // Returns the card to be refined or NULL. + // + // Increments the count for given the card. if the card is not 'hot', + // it is returned for immediate refining. Otherwise the card is + // added to the hot card cache. + // If there is enough room in the hot card cache for the card we're + // adding, NULL is returned and no further action in needed. + // If we evict a card from the cache to make room for the new card, + // the evicted card is then returned for refinement. + jbyte* insert(jbyte* card_ptr); + + // Refine the cards that have delayed as a result of + // being in the cache. + void drain(uint worker_i, G1RemSet* g1rs, DirtyCardQueue* into_cset_dcq); + + // Set up for parallel processing of the cards in the hot cache + void reset_hot_cache_claimed_index() { + _hot_cache_par_claimed_idx = 0; + } + + // Resets the hot card cache and discards the entries. + void reset_hot_cache() { + assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint"); + assert(Thread::current_noinline()->is_VM_thread(), "Current thread should be the VMthread"); + if (default_use_cache()) { + reset_hot_cache_internal(); + } + } + + // Zeros the values in the card counts table for entire committed heap + void reset_card_counts(); + + // Zeros the values in the card counts table for the given region + void reset_card_counts(HeapRegion* hr); + + private: + void reset_hot_cache_internal() { + assert(_hot_cache != NULL, "Logic"); + _hot_cache_idx = 0; + for (size_t i = 0; i < _hot_cache_size; i++) { + _hot_cache[i] = NULL; + } + } +}; + +#endif // SHARE_VM_GC_G1_G1HOTCARDCACHE_HPP