| /* |
| * Copyright (c) 1999, 2020, 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 "gc/shared/threadLocalAllocBuffer.inline.hpp" |
| #include "logging/log.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "memory/universe.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/thread.inline.hpp" |
| #include "runtime/threadSMR.hpp" |
| #include "utilities/copy.hpp" |
| |
| // Thread-Local Edens support |
| |
| // static member initialization |
| size_t ThreadLocalAllocBuffer::_max_size = 0; |
| int ThreadLocalAllocBuffer::_reserve_for_allocation_prefetch = 0; |
| unsigned ThreadLocalAllocBuffer::_target_refills = 0; |
| GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats = NULL; |
| |
| void ThreadLocalAllocBuffer::clear_before_allocation() { |
| _slow_refill_waste += (unsigned)remaining(); |
| make_parsable(true); // also retire the TLAB |
| } |
| |
| size_t ThreadLocalAllocBuffer::remaining() { |
| if (end() == NULL) { |
| return 0; |
| } |
| |
| return pointer_delta(hard_end(), top()); |
| } |
| |
| void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() { |
| global_stats()->initialize(); |
| |
| for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) { |
| thread->tlab().accumulate_statistics(); |
| thread->tlab().initialize_statistics(); |
| } |
| |
| // Publish new stats if some allocation occurred. |
| if (global_stats()->allocation() != 0) { |
| global_stats()->publish(); |
| global_stats()->print(); |
| } |
| } |
| |
| void ThreadLocalAllocBuffer::accumulate_statistics() { |
| Thread* thread = myThread(); |
| size_t capacity = Universe::heap()->tlab_capacity(thread); |
| size_t used = Universe::heap()->tlab_used(thread); |
| |
| _gc_waste += (unsigned)remaining(); |
| size_t total_allocated = thread->allocated_bytes(); |
| size_t allocated_since_last_gc = total_allocated - _allocated_before_last_gc; |
| _allocated_before_last_gc = total_allocated; |
| |
| print_stats("gc"); |
| |
| if (_number_of_refills > 0) { |
| // Update allocation history if a reasonable amount of eden was allocated. |
| bool update_allocation_history = used > 0.5 * capacity; |
| |
| if (update_allocation_history) { |
| // Average the fraction of eden allocated in a tlab by this |
| // thread for use in the next resize operation. |
| // _gc_waste is not subtracted because it's included in |
| // "used". |
| // The result can be larger than 1.0 due to direct to old allocations. |
| // These allocations should ideally not be counted but since it is not possible |
| // to filter them out here we just cap the fraction to be at most 1.0. |
| // Keep alloc_frac as float and not double to avoid the double to float conversion |
| float alloc_frac = MIN2(1.0f, allocated_since_last_gc / (float) used); |
| _allocation_fraction.sample(alloc_frac); |
| } |
| global_stats()->update_allocating_threads(); |
| global_stats()->update_number_of_refills(_number_of_refills); |
| global_stats()->update_allocation(_allocated_size); |
| global_stats()->update_gc_waste(_gc_waste); |
| global_stats()->update_slow_refill_waste(_slow_refill_waste); |
| global_stats()->update_fast_refill_waste(_fast_refill_waste); |
| |
| } else { |
| assert(_number_of_refills == 0 && _fast_refill_waste == 0 && |
| _slow_refill_waste == 0 && _gc_waste == 0, |
| "tlab stats == 0"); |
| } |
| global_stats()->update_slow_allocations(_slow_allocations); |
| } |
| |
| // Fills the current tlab with a dummy filler array to create |
| // an illusion of a contiguous Eden and optionally retires the tlab. |
| // Waste accounting should be done in caller as appropriate; see, |
| // for example, clear_before_allocation(). |
| void ThreadLocalAllocBuffer::make_parsable(bool retire, bool zap) { |
| if (end() != NULL) { |
| invariants(); |
| |
| if (retire) { |
| myThread()->incr_allocated_bytes(used_bytes()); |
| } |
| |
| Universe::heap()->fill_with_dummy_object(top(), hard_end(), retire && zap); |
| |
| if (retire || ZeroTLAB) { // "Reset" the TLAB |
| set_start(NULL); |
| set_top(NULL); |
| set_pf_top(NULL); |
| set_end(NULL); |
| set_allocation_end(NULL); |
| } |
| } |
| assert(!(retire || ZeroTLAB) || |
| (start() == NULL && end() == NULL && top() == NULL && |
| _allocation_end == NULL), |
| "TLAB must be reset"); |
| } |
| |
| void ThreadLocalAllocBuffer::resize_all_tlabs() { |
| if (ResizeTLAB) { |
| for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) { |
| thread->tlab().resize(); |
| } |
| } |
| } |
| |
| void ThreadLocalAllocBuffer::resize() { |
| // Compute the next tlab size using expected allocation amount |
| assert(ResizeTLAB, "Should not call this otherwise"); |
| size_t alloc = (size_t)(_allocation_fraction.average() * |
| (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize)); |
| size_t new_size = alloc / _target_refills; |
| |
| new_size = MIN2(MAX2(new_size, min_size()), max_size()); |
| |
| size_t aligned_new_size = align_object_size(new_size); |
| |
| log_trace(gc, tlab)("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]" |
| " refills %d alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT, |
| p2i(myThread()), myThread()->osthread()->thread_id(), |
| _target_refills, _allocation_fraction.average(), desired_size(), aligned_new_size); |
| |
| set_desired_size(aligned_new_size); |
| set_refill_waste_limit(initial_refill_waste_limit()); |
| } |
| |
| void ThreadLocalAllocBuffer::initialize_statistics() { |
| _number_of_refills = 0; |
| _fast_refill_waste = 0; |
| _slow_refill_waste = 0; |
| _gc_waste = 0; |
| _slow_allocations = 0; |
| _allocated_size = 0; |
| } |
| |
| void ThreadLocalAllocBuffer::fill(HeapWord* start, |
| HeapWord* top, |
| size_t new_size) { |
| _number_of_refills++; |
| _allocated_size += new_size; |
| print_stats("fill"); |
| assert(top <= start + new_size - alignment_reserve(), "size too small"); |
| |
| initialize(start, top, start + new_size - alignment_reserve()); |
| |
| // Reset amount of internal fragmentation |
| set_refill_waste_limit(initial_refill_waste_limit()); |
| } |
| |
| void ThreadLocalAllocBuffer::initialize(HeapWord* start, |
| HeapWord* top, |
| HeapWord* end) { |
| set_start(start); |
| set_top(top); |
| set_pf_top(top); |
| set_end(end); |
| set_allocation_end(end); |
| invariants(); |
| } |
| |
| void ThreadLocalAllocBuffer::initialize() { |
| initialize(NULL, // start |
| NULL, // top |
| NULL); // end |
| |
| set_desired_size(initial_desired_size()); |
| |
| // Following check is needed because at startup the main |
| // thread is initialized before the heap is. The initialization for |
| // this thread is redone in startup_initialization below. |
| if (Universe::heap() != NULL) { |
| size_t capacity = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize; |
| // Keep alloc_frac as float and not double to avoid the double to float conversion |
| float alloc_frac = desired_size() * target_refills() / (float) capacity; |
| _allocation_fraction.sample(alloc_frac); |
| } |
| |
| set_refill_waste_limit(initial_refill_waste_limit()); |
| |
| initialize_statistics(); |
| } |
| |
| void ThreadLocalAllocBuffer::startup_initialization() { |
| |
| // Assuming each thread's active tlab is, on average, |
| // 1/2 full at a GC |
| _target_refills = 100 / (2 * TLABWasteTargetPercent); |
| // We need to set initial target refills to 2 to avoid a GC which causes VM |
| // abort during VM initialization. |
| _target_refills = MAX2(_target_refills, 2U); |
| |
| _global_stats = new GlobalTLABStats(); |
| |
| #ifdef COMPILER2 |
| // If the C2 compiler is present, extra space is needed at the end of |
| // TLABs, otherwise prefetching instructions generated by the C2 |
| // compiler will fault (due to accessing memory outside of heap). |
| // The amount of space is the max of the number of lines to |
| // prefetch for array and for instance allocations. (Extra space must be |
| // reserved to accommodate both types of allocations.) |
| // |
| // Only SPARC-specific BIS instructions are known to fault. (Those |
| // instructions are generated if AllocatePrefetchStyle==3 and |
| // AllocatePrefetchInstr==1). To be on the safe side, however, |
| // extra space is reserved for all combinations of |
| // AllocatePrefetchStyle and AllocatePrefetchInstr. |
| // |
| // If the C2 compiler is not present, no space is reserved. |
| |
| // +1 for rounding up to next cache line, +1 to be safe |
| if (is_server_compilation_mode_vm()) { |
| int lines = MAX2(AllocatePrefetchLines, AllocateInstancePrefetchLines) + 2; |
| _reserve_for_allocation_prefetch = (AllocatePrefetchDistance + AllocatePrefetchStepSize * lines) / |
| (int)HeapWordSize; |
| } |
| #endif |
| |
| // During jvm startup, the main thread is initialized |
| // before the heap is initialized. So reinitialize it now. |
| guarantee(Thread::current()->is_Java_thread(), "tlab initialization thread not Java thread"); |
| Thread::current()->tlab().initialize(); |
| |
| log_develop_trace(gc, tlab)("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT, |
| min_size(), Thread::current()->tlab().initial_desired_size(), max_size()); |
| } |
| |
| size_t ThreadLocalAllocBuffer::initial_desired_size() { |
| size_t init_sz = 0; |
| |
| if (TLABSize > 0) { |
| init_sz = TLABSize / HeapWordSize; |
| } else if (global_stats() != NULL) { |
| // Initial size is a function of the average number of allocating threads. |
| unsigned nof_threads = global_stats()->allocating_threads_avg(); |
| |
| init_sz = (Universe::heap()->tlab_capacity(myThread()) / HeapWordSize) / |
| (nof_threads * target_refills()); |
| init_sz = align_object_size(init_sz); |
| } |
| init_sz = MIN2(MAX2(init_sz, min_size()), max_size()); |
| return init_sz; |
| } |
| |
| void ThreadLocalAllocBuffer::print_stats(const char* tag) { |
| Log(gc, tlab) log; |
| if (!log.is_trace()) { |
| return; |
| } |
| |
| Thread* thrd = myThread(); |
| size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste; |
| double waste_percent = percent_of(waste, _allocated_size); |
| size_t tlab_used = Universe::heap()->tlab_used(thrd); |
| log.trace("TLAB: %s thread: " INTPTR_FORMAT " [id: %2d]" |
| " desired_size: " SIZE_FORMAT "KB" |
| " slow allocs: %d refill waste: " SIZE_FORMAT "B" |
| " alloc:%8.5f %8.0fKB refills: %d waste %4.1f%% gc: %dB" |
| " slow: %dB fast: %dB", |
| tag, p2i(thrd), thrd->osthread()->thread_id(), |
| _desired_size / (K / HeapWordSize), |
| _slow_allocations, _refill_waste_limit * HeapWordSize, |
| _allocation_fraction.average(), |
| _allocation_fraction.average() * tlab_used / K, |
| _number_of_refills, waste_percent, |
| _gc_waste * HeapWordSize, |
| _slow_refill_waste * HeapWordSize, |
| _fast_refill_waste * HeapWordSize); |
| } |
| |
| void ThreadLocalAllocBuffer::verify() { |
| HeapWord* p = start(); |
| HeapWord* t = top(); |
| HeapWord* prev_p = NULL; |
| while (p < t) { |
| oop(p)->verify(); |
| prev_p = p; |
| p += oop(p)->size(); |
| } |
| guarantee(p == top(), "end of last object must match end of space"); |
| } |
| |
| void ThreadLocalAllocBuffer::set_sample_end() { |
| size_t heap_words_remaining = pointer_delta(_end, _top); |
| size_t bytes_until_sample = myThread()->heap_sampler().bytes_until_sample(); |
| size_t words_until_sample = bytes_until_sample / HeapWordSize; |
| |
| if (heap_words_remaining > words_until_sample) { |
| HeapWord* new_end = _top + words_until_sample; |
| set_end(new_end); |
| _bytes_since_last_sample_point = bytes_until_sample; |
| } else { |
| _bytes_since_last_sample_point = heap_words_remaining * HeapWordSize; |
| } |
| } |
| |
| Thread* ThreadLocalAllocBuffer::myThread() { |
| return (Thread*)(((char *)this) + |
| in_bytes(start_offset()) - |
| in_bytes(Thread::tlab_start_offset())); |
| } |
| |
| void ThreadLocalAllocBuffer::set_back_allocation_end() { |
| _end = _allocation_end; |
| } |
| |
| HeapWord* ThreadLocalAllocBuffer::hard_end() { |
| return _allocation_end + alignment_reserve(); |
| } |
| |
| GlobalTLABStats::GlobalTLABStats() : |
| _allocating_threads_avg(TLABAllocationWeight) { |
| |
| initialize(); |
| |
| _allocating_threads_avg.sample(1); // One allocating thread at startup |
| |
| if (UsePerfData) { |
| |
| EXCEPTION_MARK; |
| ResourceMark rm; |
| |
| char* cname = PerfDataManager::counter_name("tlab", "allocThreads"); |
| _perf_allocating_threads = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "fills"); |
| _perf_total_refills = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "maxFills"); |
| _perf_max_refills = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "alloc"); |
| _perf_allocation = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "gcWaste"); |
| _perf_gc_waste = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "maxGcWaste"); |
| _perf_max_gc_waste = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "slowWaste"); |
| _perf_slow_refill_waste = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "maxSlowWaste"); |
| _perf_max_slow_refill_waste = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "fastWaste"); |
| _perf_fast_refill_waste = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "maxFastWaste"); |
| _perf_max_fast_refill_waste = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_Bytes, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "slowAlloc"); |
| _perf_slow_allocations = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); |
| |
| cname = PerfDataManager::counter_name("tlab", "maxSlowAlloc"); |
| _perf_max_slow_allocations = |
| PerfDataManager::create_variable(SUN_GC, cname, PerfData::U_None, CHECK); |
| } |
| } |
| |
| void GlobalTLABStats::initialize() { |
| // Clear counters summarizing info from all threads |
| _allocating_threads = 0; |
| _total_refills = 0; |
| _max_refills = 0; |
| _total_allocation = 0; |
| _total_gc_waste = 0; |
| _max_gc_waste = 0; |
| _total_slow_refill_waste = 0; |
| _max_slow_refill_waste = 0; |
| _total_fast_refill_waste = 0; |
| _max_fast_refill_waste = 0; |
| _total_slow_allocations = 0; |
| _max_slow_allocations = 0; |
| } |
| |
| void GlobalTLABStats::publish() { |
| _allocating_threads_avg.sample(_allocating_threads); |
| if (UsePerfData) { |
| _perf_allocating_threads ->set_value(_allocating_threads); |
| _perf_total_refills ->set_value(_total_refills); |
| _perf_max_refills ->set_value(_max_refills); |
| _perf_allocation ->set_value(_total_allocation); |
| _perf_gc_waste ->set_value(_total_gc_waste); |
| _perf_max_gc_waste ->set_value(_max_gc_waste); |
| _perf_slow_refill_waste ->set_value(_total_slow_refill_waste); |
| _perf_max_slow_refill_waste->set_value(_max_slow_refill_waste); |
| _perf_fast_refill_waste ->set_value(_total_fast_refill_waste); |
| _perf_max_fast_refill_waste->set_value(_max_fast_refill_waste); |
| _perf_slow_allocations ->set_value(_total_slow_allocations); |
| _perf_max_slow_allocations ->set_value(_max_slow_allocations); |
| } |
| } |
| |
| void GlobalTLABStats::print() { |
| Log(gc, tlab) log; |
| if (!log.is_debug()) { |
| return; |
| } |
| |
| size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste; |
| double waste_percent = percent_of(waste, _total_allocation); |
| log.debug("TLAB totals: thrds: %d refills: %d max: %d" |
| " slow allocs: %d max %d waste: %4.1f%%" |
| " gc: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" |
| " slow: " SIZE_FORMAT "B max: " SIZE_FORMAT "B" |
| " fast: " SIZE_FORMAT "B max: " SIZE_FORMAT "B", |
| _allocating_threads, |
| _total_refills, _max_refills, |
| _total_slow_allocations, _max_slow_allocations, |
| waste_percent, |
| _total_gc_waste * HeapWordSize, |
| _max_gc_waste * HeapWordSize, |
| _total_slow_refill_waste * HeapWordSize, |
| _max_slow_refill_waste * HeapWordSize, |
| _total_fast_refill_waste * HeapWordSize, |
| _max_fast_refill_waste * HeapWordSize); |
| } |
