Mercurial > hg > graal-compiler
view src/share/vm/utilities/taskqueue.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 | f08d439fab8c |
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/* * Copyright (c) 2001, 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 "oops/oop.inline.hpp" #include "runtime/os.hpp" #include "utilities/debug.hpp" #include "utilities/stack.inline.hpp" #include "utilities/taskqueue.hpp" #ifdef TARGET_OS_FAMILY_linux # include "thread_linux.inline.hpp" #endif #ifdef TARGET_OS_FAMILY_solaris # include "thread_solaris.inline.hpp" #endif #ifdef TARGET_OS_FAMILY_windows # include "thread_windows.inline.hpp" #endif #ifdef TRACESPINNING uint ParallelTaskTerminator::_total_yields = 0; uint ParallelTaskTerminator::_total_spins = 0; uint ParallelTaskTerminator::_total_peeks = 0; #endif #if TASKQUEUE_STATS const char * const TaskQueueStats::_names[last_stat_id] = { "qpush", "qpop", "qpop-s", "qattempt", "qsteal", "opush", "omax" }; TaskQueueStats & TaskQueueStats::operator +=(const TaskQueueStats & addend) { for (unsigned int i = 0; i < last_stat_id; ++i) { _stats[i] += addend._stats[i]; } return *this; } void TaskQueueStats::print_header(unsigned int line, outputStream* const stream, unsigned int width) { // Use a width w: 1 <= w <= max_width const unsigned int max_width = 40; const unsigned int w = MAX2(MIN2(width, max_width), 1U); if (line == 0) { // spaces equal in width to the header const unsigned int hdr_width = w * last_stat_id + last_stat_id - 1; stream->print("%*s", hdr_width, " "); } else if (line == 1) { // labels stream->print("%*s", w, _names[0]); for (unsigned int i = 1; i < last_stat_id; ++i) { stream->print(" %*s", w, _names[i]); } } else if (line == 2) { // dashed lines char dashes[max_width + 1]; memset(dashes, '-', w); dashes[w] = '\0'; stream->print("%s", dashes); for (unsigned int i = 1; i < last_stat_id; ++i) { stream->print(" %s", dashes); } } } void TaskQueueStats::print(outputStream* stream, unsigned int width) const { #define FMT SIZE_FORMAT_W(*) stream->print(FMT, width, _stats[0]); for (unsigned int i = 1; i < last_stat_id; ++i) { stream->print(" " FMT, width, _stats[i]); } #undef FMT } #ifdef ASSERT // Invariants which should hold after a TaskQueue has been emptied and is // quiescent; they do not hold at arbitrary times. void TaskQueueStats::verify() const { assert(get(push) == get(pop) + get(steal), err_msg("push=" SIZE_FORMAT " pop=" SIZE_FORMAT " steal=" SIZE_FORMAT, get(push), get(pop), get(steal))); assert(get(pop_slow) <= get(pop), err_msg("pop_slow=" SIZE_FORMAT " pop=" SIZE_FORMAT, get(pop_slow), get(pop))); assert(get(steal) <= get(steal_attempt), err_msg("steal=" SIZE_FORMAT " steal_attempt=" SIZE_FORMAT, get(steal), get(steal_attempt))); assert(get(overflow) == 0 || get(push) != 0, err_msg("overflow=" SIZE_FORMAT " push=" SIZE_FORMAT, get(overflow), get(push))); assert(get(overflow_max_len) == 0 || get(overflow) != 0, err_msg("overflow_max_len=" SIZE_FORMAT " overflow=" SIZE_FORMAT, get(overflow_max_len), get(overflow))); } #endif // ASSERT #endif // TASKQUEUE_STATS int TaskQueueSetSuper::randomParkAndMiller(int *seed0) { const int a = 16807; const int m = 2147483647; const int q = 127773; /* m div a */ const int r = 2836; /* m mod a */ assert(sizeof(int) == 4, "I think this relies on that"); int seed = *seed0; int hi = seed / q; int lo = seed % q; int test = a * lo - r * hi; if (test > 0) seed = test; else seed = test + m; *seed0 = seed; return seed; } ParallelTaskTerminator:: ParallelTaskTerminator(int n_threads, TaskQueueSetSuper* queue_set) : _n_threads(n_threads), _queue_set(queue_set), _offered_termination(0) {} bool ParallelTaskTerminator::peek_in_queue_set() { return _queue_set->peek(); } void ParallelTaskTerminator::yield() { assert(_offered_termination <= _n_threads, "Invariant"); os::yield(); } void ParallelTaskTerminator::sleep(uint millis) { assert(_offered_termination <= _n_threads, "Invariant"); os::sleep(Thread::current(), millis, false); } bool ParallelTaskTerminator::offer_termination(TerminatorTerminator* terminator) { assert(_n_threads > 0, "Initialization is incorrect"); assert(_offered_termination < _n_threads, "Invariant"); Atomic::inc(&_offered_termination); uint yield_count = 0; // Number of hard spin loops done since last yield uint hard_spin_count = 0; // Number of iterations in the hard spin loop. uint hard_spin_limit = WorkStealingHardSpins; // If WorkStealingSpinToYieldRatio is 0, no hard spinning is done. // If it is greater than 0, then start with a small number // of spins and increase number with each turn at spinning until // the count of hard spins exceeds WorkStealingSpinToYieldRatio. // Then do a yield() call and start spinning afresh. if (WorkStealingSpinToYieldRatio > 0) { hard_spin_limit = WorkStealingHardSpins >> WorkStealingSpinToYieldRatio; hard_spin_limit = MAX2(hard_spin_limit, 1U); } // Remember the initial spin limit. uint hard_spin_start = hard_spin_limit; // Loop waiting for all threads to offer termination or // more work. while (true) { assert(_offered_termination <= _n_threads, "Invariant"); // Are all threads offering termination? if (_offered_termination == _n_threads) { return true; } else { // Look for more work. // Periodically sleep() instead of yield() to give threads // waiting on the cores the chance to grab this code if (yield_count <= WorkStealingYieldsBeforeSleep) { // Do a yield or hardspin. For purposes of deciding whether // to sleep, count this as a yield. yield_count++; // Periodically call yield() instead spinning // After WorkStealingSpinToYieldRatio spins, do a yield() call // and reset the counts and starting limit. if (hard_spin_count > WorkStealingSpinToYieldRatio) { yield(); hard_spin_count = 0; hard_spin_limit = hard_spin_start; #ifdef TRACESPINNING _total_yields++; #endif } else { // Hard spin this time // Increase the hard spinning period but only up to a limit. hard_spin_limit = MIN2(2*hard_spin_limit, (uint) WorkStealingHardSpins); for (uint j = 0; j < hard_spin_limit; j++) { SpinPause(); } hard_spin_count++; #ifdef TRACESPINNING _total_spins++; #endif } } else { if (PrintGCDetails && Verbose) { gclog_or_tty->print_cr("ParallelTaskTerminator::offer_termination() " "thread %d sleeps after %d yields", Thread::current(), yield_count); } yield_count = 0; // A sleep will cause this processor to seek work on another processor's // runqueue, if it has nothing else to run (as opposed to the yield // which may only move the thread to the end of the this processor's // runqueue). sleep(WorkStealingSleepMillis); } #ifdef TRACESPINNING _total_peeks++; #endif if (peek_in_queue_set() || (terminator != NULL && terminator->should_exit_termination())) { Atomic::dec(&_offered_termination); assert(_offered_termination < _n_threads, "Invariant"); return false; } } } } #ifdef TRACESPINNING void ParallelTaskTerminator::print_termination_counts() { gclog_or_tty->print_cr("ParallelTaskTerminator Total yields: %lld " "Total spins: %lld Total peeks: %lld", total_yields(), total_spins(), total_peeks()); } #endif void ParallelTaskTerminator::reset_for_reuse() { if (_offered_termination != 0) { assert(_offered_termination == _n_threads, "Terminator may still be in use"); _offered_termination = 0; } } #ifdef ASSERT bool ObjArrayTask::is_valid() const { return _obj != NULL && _obj->is_objArray() && _index > 0 && _index < objArrayOop(_obj)->length(); } #endif // ASSERT void ParallelTaskTerminator::reset_for_reuse(int n_threads) { reset_for_reuse(); _n_threads = n_threads; }