aoqi@0: /*
aoqi@0:  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_RUNTIME_RTMLOCKING_HPP
aoqi@0: #define SHARE_VM_RUNTIME_RTMLOCKING_HPP
aoqi@0: 
aoqi@0: // Generate RTM (Restricted Transactional Memory) locking code for all inflated
aoqi@0: // locks when "UseRTMLocking" option is on with normal locking mechanism as fall back
aoqi@0: // handler.
aoqi@0: //
aoqi@0: // On abort/lock busy the lock will be retried a fixed number of times under RTM
aoqi@0: // as specified by "RTMRetryCount" option. The locks which abort too often
aoqi@0: // can be auto tuned or manually tuned.
aoqi@0: //
aoqi@0: // Auto-tuning can be done on an option like UseRTMDeopt and it will need abort
aoqi@0: // ratio calculation for each lock. The abort ratio will be calculated after
aoqi@0: // "RTMAbortThreshold" number of aborts is reached. The formulas are:
aoqi@0: //
aoqi@0: //     Aborted transactions = abort_count * 100
aoqi@0: //     All transactions = total_count *  RTMTotalCountIncrRate
aoqi@0: //
aoqi@0: //     Aborted transactions >= All transactions * RTMAbortRatio
aoqi@0: //
aoqi@0: // If "UseRTMDeopt" is on and the aborts ratio reaches "RTMAbortRatio"
aoqi@0: // the method containing the lock will be deoptimized and recompiled with
aoqi@0: // all locks as normal locks. If the abort ratio continues to remain low after
aoqi@0: // "RTMLockingThreshold" locks are attempted, then the method will be deoptimized
aoqi@0: // and recompiled with all locks as RTM locks without abort ratio calculation code.
aoqi@0: // The abort ratio calculation can be delayed by specifying flag
aoqi@0: // -XX:RTMLockingCalculationDelay in millisecond.
aoqi@0: //
aoqi@0: // For manual tuning the abort statistics for each lock needs to be provided
aoqi@0: // to the user on some JVM option like "PrintPreciseRTMLockingStatistics".
aoqi@0: // Based on the abort statistics users can create a .hotspot_compiler file
aoqi@0: // or use -XX:CompileCommand=option,class::method,NoRTMLockEliding
aoqi@0: // to specify for which methods to disable RTM locking.
aoqi@0: //
aoqi@0: // When UseRTMForStackLocks option is enabled along with UseRTMLocking option,
aoqi@0: // the RTM locking code is generated for stack locks too.
aoqi@0: // The retries, auto-tuning support and rtm locking statistics are all
aoqi@0: // supported for stack locks just like inflated locks.
aoqi@0: 
aoqi@0: // RTM locking counters
aoqi@0: class RTMLockingCounters VALUE_OBJ_CLASS_SPEC {
aoqi@0:  private:
aoqi@0:   uintx _total_count; // Total RTM locks count
aoqi@0:   uintx _abort_count; // Total aborts count
aoqi@0: 
aoqi@0:  public:
aoqi@0:   enum { ABORT_STATUS_LIMIT = 6 };
aoqi@0:   // Counters per RTM Abort Status. Incremented with +PrintPreciseRTMLockingStatistics
aoqi@0:   // RTM uses the EAX register to communicate abort status to software.
aoqi@0:   // Following an RTM abort the EAX register has the following definition.
aoqi@0:   //
aoqi@0:   //   EAX register bit position   Meaning
aoqi@0:   //     0     Set if abort caused by XABORT instruction.
aoqi@0:   //     1     If set, the transaction may succeed on a retry. This bit is always clear if bit 0 is set.
aoqi@0:   //     2     Set if another logical processor conflicted with a memory address that was part of the transaction that aborted.
aoqi@0:   //     3     Set if an internal buffer overflowed.
aoqi@0:   //     4     Set if a debug breakpoint was hit.
aoqi@0:   //     5     Set if an abort occurred during execution of a nested transaction.
aoqi@0:  private:
aoqi@0:   uintx _abortX_count[ABORT_STATUS_LIMIT];
aoqi@0: 
aoqi@0:  public:
aoqi@0:   static uintx _calculation_flag;
aoqi@0:   static uintx* rtm_calculation_flag_addr() { return &_calculation_flag; }
aoqi@0: 
aoqi@0:   static void init();
aoqi@0: 
aoqi@0:   RTMLockingCounters() : _total_count(0), _abort_count(0) {
aoqi@0:     for (int i = 0; i < ABORT_STATUS_LIMIT; i++) {
aoqi@0:       _abortX_count[i] = 0;
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0:   uintx* total_count_addr()               { return &_total_count; }
aoqi@0:   uintx* abort_count_addr()               { return &_abort_count; }
aoqi@0:   uintx* abortX_count_addr()              { return &_abortX_count[0]; }
aoqi@0: 
aoqi@0:   static int total_count_offset()         { return (int)offset_of(RTMLockingCounters, _total_count); }
aoqi@0:   static int abort_count_offset()         { return (int)offset_of(RTMLockingCounters, _abort_count); }
aoqi@0:   static int abortX_count_offset()        { return (int)offset_of(RTMLockingCounters, _abortX_count[0]); }
aoqi@0: 
aoqi@0: 
aoqi@0:   bool nonzero() {  return (_abort_count + _total_count) > 0; }
aoqi@0: 
aoqi@0:   void print_on(outputStream* st);
aoqi@0:   void print() { print_on(tty); }
aoqi@0: };
aoqi@0: 
aoqi@0: #endif // SHARE_VM_RUNTIME_RTMLOCKING_HPP