--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/shared/threadLocalAllocBuffer.cpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,409 @@
+/*
+ * Copyright (c) 1999, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc/shared/genCollectedHeap.hpp"
+#include "gc/shared/threadLocalAllocBuffer.inline.hpp"
+#include "memory/resourceArea.hpp"
+#include "memory/universe.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/thread.inline.hpp"
+#include "utilities/copy.hpp"
+
+// Thread-Local Edens support
+
+// static member initialization
+size_t ThreadLocalAllocBuffer::_max_size = 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
+}
+
+void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
+ global_stats()->initialize();
+
+ for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
+ thread->tlab().accumulate_statistics();
+ thread->tlab().initialize_statistics();
+ }
+
+ // Publish new stats if some allocation occurred.
+ if (global_stats()->allocation() != 0) {
+ global_stats()->publish();
+ if (PrintTLAB) {
+ 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;
+
+ if (PrintTLAB && (_number_of_refills > 0 || Verbose)) {
+ 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.
+ double alloc_frac = MIN2(1.0, (double) allocated_since_last_gc / used);
+ _allocation_fraction.sample(alloc_frac);
+ }
+ global_stats()->update_allocating_threads();
+ global_stats()->update_number_of_refills(_number_of_refills);
+ global_stats()->update_allocation(_number_of_refills * desired_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) {
+ if (end() != NULL) {
+ invariants();
+
+ if (retire) {
+ myThread()->incr_allocated_bytes(used_bytes());
+ }
+
+ CollectedHeap::fill_with_object(top(), hard_end(), retire);
+
+ if (retire || ZeroTLAB) { // "Reset" the TLAB
+ set_start(NULL);
+ set_top(NULL);
+ set_pf_top(NULL);
+ set_end(NULL);
+ }
+ }
+ assert(!(retire || ZeroTLAB) ||
+ (start() == NULL && end() == NULL && top() == NULL),
+ "TLAB must be reset");
+}
+
+void ThreadLocalAllocBuffer::resize_all_tlabs() {
+ if (ResizeTLAB) {
+ for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->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);
+
+ if (PrintTLAB && Verbose) {
+ gclog_or_tty->print("TLAB new size: thread: " INTPTR_FORMAT " [id: %2d]"
+ " refills %d alloc: %8.6f desired_size: " SIZE_FORMAT " -> " SIZE_FORMAT "\n",
+ 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;
+}
+
+void ThreadLocalAllocBuffer::fill(HeapWord* start,
+ HeapWord* top,
+ size_t new_size) {
+ _number_of_refills++;
+ if (PrintTLAB && Verbose) {
+ 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);
+ 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 (primordial)
+ // 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;
+ double alloc_frac = desired_size() * target_refills() / (double) 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);
+ _target_refills = MAX2(_target_refills, (unsigned)1U);
+
+ _global_stats = new GlobalTLABStats();
+
+ // During jvm startup, the main (primordial) 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();
+
+ if (PrintTLAB && Verbose) {
+ gclog_or_tty->print("TLAB min: " SIZE_FORMAT " initial: " SIZE_FORMAT " max: " SIZE_FORMAT "\n",
+ 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) {
+ Thread* thrd = myThread();
+ size_t waste = _gc_waste + _slow_refill_waste + _fast_refill_waste;
+ size_t alloc = _number_of_refills * _desired_size;
+ double waste_percent = alloc == 0 ? 0.0 :
+ 100.0 * waste / alloc;
+ size_t tlab_used = Universe::heap()->tlab_used(thrd);
+ gclog_or_tty->print("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\n",
+ 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");
+}
+
+Thread* ThreadLocalAllocBuffer::myThread() {
+ return (Thread*)(((char *)this) +
+ in_bytes(start_offset()) -
+ in_bytes(Thread::tlab_start_offset()));
+}
+
+
+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() {
+ size_t waste = _total_gc_waste + _total_slow_refill_waste + _total_fast_refill_waste;
+ double waste_percent = _total_allocation == 0 ? 0.0 :
+ 100.0 * waste / _total_allocation;
+ gclog_or_tty->print("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\n",
+ _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);
+}