--- /dev/null 2014-03-17 11:39:43.000000000 -0700 +++ new/src/share/vm/runtime/rtmLocking.hpp 2014-03-17 11:39:43.000000000 -0700 @@ -0,0 +1,113 @@ +/* + * Copyright (c) 2014, 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_RUNTIME_RTMLOCKING_HPP +#define SHARE_VM_RUNTIME_RTMLOCKING_HPP + +// Generate RTM (Restricted Transactional Memory) locking code for all inflated +// locks when "UseRTM" option is on with normal locking mechanism as fall back +// handler. +// +// On abort/lock busy the lock will be retried a fixed number of times under RTM +// as specified by "RTMRetryCount" option. The locks which abort too often +// can be auto tuned or manually tuned. +// +// Auto-tuning can be done on an option like UseRTMDeopt and it will need abort +// ratio calculation for each lock. The abort ratio will be calculated after +// "RTMAbortThreshold" number of aborts is reached. The formulas are: +// +// Aborted transactions = abort_count * 100 +// All transactions = total_count * RTMTotalCountIncrRate +// +// Aborted transactions >= All transactions * RTMAbortRatio +// +// If "UseRTMDeopt" is on and the aborts ratio reaches "RTMAbortRatio" +// the method containing the lock will be deoptimized and recompiled with +// all locks as normal locks. If the abort ratio continues to remain low after +// "RTMLockingThreshold" locks are attempted, then the method will be deoptimized +// and recompiled with all locks as RTM locks without abort ratio calculation code. +// The abort ratio calculation can be delayed by specifying flag +// -XX:RTMLockingCalculationDelay in millisecond. +// +// For manual tuning the abort statistics for each lock needs to be provided +// to the user on some JVM option like "PrintPreciseRTMLockingStatistics". +// Based on the abort statistics users can create a .hotspot_compiler file +// or use -XX:CompileCommnad=option,class::method,DoNotElide +// to specify for which methods to disable RTM locking. +// +// When UseRTMForStackLocks option is enabled along with UseRTMLocking option, +// the RTM locking code is generated for stack locks too. +// The retries, auto-tuning support and rtm locking statistics are all +// supported for stack locks just like inflated locks. + +// RTM locking counters +class RTMLockingCounters VALUE_OBJ_CLASS_SPEC { + private: + uintx _total_count; // Total RTM locks count + uintx _abort_count; // Total aborts count + + public: + enum { ABORT_STATUS_LIMIT = 6 }; + // Counters per RTM Abort Status. Incremented with +PrintPreciseRTMLockingStatistics + // RTM uses the EAX register to communicate abort status to software. + // Following an RTM abort the EAX register has the following definition. + // + // EAX register bit position Meaning + // 0 Set if abort caused by XABORT instruction. + // 1 If set, the transaction may succeed on a retry. This bit is always clear if bit 0 is set. + // 2 Set if another logical processor conflicted with a memory address that was part of the transaction that aborted. + // 3 Set if an internal buffer overflowed. + // 4 Set if a debug breakpoint was hit. + // 5 Set if an abort occurred during execution of a nested transaction. + private: + uintx _abortX_count[ABORT_STATUS_LIMIT]; + + public: + static uintx _calculation_flag; + static uintx* rtm_calculation_flag() { return &_calculation_flag; } + + static void init(); + + RTMLockingCounters() : _total_count(0), _abort_count(0) { + for (int i = 0; i < ABORT_STATUS_LIMIT; i++) { + _abortX_count[i] = 0; + } + } + + uintx* total_count_addr() { return &_total_count; } + uintx* abort_count_addr() { return &_abort_count; } + uintx* abortX_count_addr() { return &_abortX_count[0]; } + + static int total_count_offset() { return (int)offset_of(RTMLockingCounters, _total_count); } + static int abort_count_offset() { return (int)offset_of(RTMLockingCounters, _abort_count); } + static int abortX_count_offset() { return (int)offset_of(RTMLockingCounters, _abortX_count[0]); } + + + bool nonzero() { return (_abort_count+_total_count) > 0; } + + void print_on(outputStream* st); + void print() { print_on(tty); } +}; + +#endif // SHARE_VM_RUNTIME_RTMLOCKING_HPP