jdk8-mips64-public/hotspot: src/share/vm/utilities/events.cpp@c96030fff130 (annotated)

src/share/vm/utilities/events.cpp@c96030fff130 (annotated)

src/share/vm/utilities/events.cpp

Thu, 20 Nov 2008 16:56:09 -0800

author: ysr
date: Thu, 20 Nov 2008 16:56:09 -0800
changeset 888: c96030fff130
parent 435: a61af66fc99e
child 1907: c18cbe5936b8
permissions: -rw-r--r--

6684579: SoftReference processing can be made more efficient
Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa

 /*
  * Copyright 1997-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 #include "incls/_precompiled.incl"
 #include "incls/_events.cpp.incl"
 #ifndef PRODUCT
 ////////////////////////////////////////////////////////////////////////////
 // Event
 typedef u4 EventID;
 class Event VALUE_OBJ_CLASS_SPEC  {
  private:
   jlong       _time_tick;
   intx        _thread_id;
   const char* _format;
   int         _indent;
   intptr_t    _arg_1;
   intptr_t    _arg_2;
   intptr_t    _arg_3;
   // only EventBuffer::add_event() can assign event id
   friend class EventBuffer;
   EventID     _id;
  public:
   void clear() { _format = NULL; }
   EventID id() const { return _id; }
   void fill(int indent, const char* format, intptr_t arg_1, intptr_t arg_2, intptr_t arg_3) {
     _format = format;
     _arg_1  = arg_1;
     _arg_2  = arg_2;
     _arg_3  = arg_3;
     _indent = indent;
     _thread_id = os::current_thread_id();
     _time_tick = os::elapsed_counter();
   }
   void print_on(outputStream *st) {
     if (_format == NULL) return;
     st->print("  %d", _thread_id);
     st->print("  %3.2g   ", (double)_time_tick / os::elapsed_frequency());
     st->fill_to(20);
     for (int index = 0; index < _indent; index++) {
       st->print("| ");
     }
     st->print_cr(_format, _arg_1, _arg_2, _arg_3);
   }
 };
 ////////////////////////////////////////////////////////////////////////////
 // EventBuffer
 //
 // Simple lock-free event queue. Every event has a unique 32-bit id.
 // It's fine if two threads add events at the same time, because they
 // will get different event id, and then write to different buffer location.
 // However, it is assumed that add_event() is quick enough (or buffer size
 // is big enough), so when one thread is adding event, there can't be more
 // than "size" events created by other threads; otherwise we'll end up having
 // two threads writing to the same location.
 class EventBuffer : AllStatic {
  private:
   static Event* buffer;
   static int    size;
   static jint   indent;
   static volatile EventID _current_event_id;
   static EventID get_next_event_id() {
     return (EventID)Atomic::add(1, (jint*)&_current_event_id);
   }
  public:
   static void inc_indent() { Atomic::inc(&indent); }
   static void dec_indent() { Atomic::dec(&indent); }
   static bool get_event(EventID id, Event* event) {
     int index = (int)(id % size);
     if (buffer[index].id() == id) {
       memcpy(event, &buffer[index], sizeof(Event));
       // check id again; if buffer[index] is being updated by another thread,
       // event->id() will contain different value.
       return (event->id() == id);
     } else {
       // id does not match - id is invalid, or event is overwritten
       return false;
     }
   }
   // add a new event to the queue; if EventBuffer is full, this call will
   // overwrite the oldest event in the queue
   static EventID add_event(const char* format,
                            intptr_t arg_1, intptr_t arg_2, intptr_t arg_3) {
     // assign a unique id
     EventID id = get_next_event_id();
     // event will be copied to buffer[index]
     int index = (int)(id % size);
     // first, invalidate id, buffer[index] can't have event with id = index + 2
     buffer[index]._id = index + 2;
     // make sure everyone has seen that buffer[index] is invalid
     OrderAccess::fence();
     // ... before updating its value
     buffer[index].fill(indent, format, arg_1, arg_2, arg_3);
     // finally, set up real event id, now buffer[index] contains valid event
     OrderAccess::release_store(&(buffer[index]._id), id);
     return id;
   }
   static void print_last(outputStream *st, int number) {
     st->print_cr("[Last %d events in the event buffer]", number);
     st->print_cr("-<thd>-<elapsed sec>-<description>---------------------");
     int count = 0;
     EventID id = _current_event_id;
     while (count < number) {
       Event event;
       if (get_event(id, &event)) {
          event.print_on(st);
       }
       id--;
       count++;
     }
   }
   static void print_all(outputStream* st) {
     print_last(st, size);
   }
   static void init() {
     // Allocate the event buffer
     size   = EventLogLength;
     buffer = NEW_C_HEAP_ARRAY(Event, size);
     _current_event_id = 0;
     // Clear the event buffer
     for (int index = 0; index < size; index++) {
       buffer[index]._id = index + 1;       // index + 1 is invalid id
       buffer[index].clear();
     }
   }
 };
 Event*           EventBuffer::buffer;
 int              EventBuffer::size;
 volatile EventID EventBuffer::_current_event_id;
 int              EventBuffer::indent;
 ////////////////////////////////////////////////////////////////////////////
 // Events
 // Events::log() is safe for signal handlers
 void Events::log(const char* format, ...) {
   if (LogEvents) {
     va_list ap;
     va_start(ap, format);
     intptr_t arg_1 = va_arg(ap, intptr_t);
     intptr_t arg_2 = va_arg(ap, intptr_t);
     intptr_t arg_3 = va_arg(ap, intptr_t);
     va_end(ap);
     EventBuffer::add_event(format, arg_1, arg_2, arg_3);
   }
 }
 void Events::print_all(outputStream *st) {
   EventBuffer::print_all(st);
 }
 void Events::print_last(outputStream *st, int number) {
   EventBuffer::print_last(st, number);
 }
 ///////////////////////////////////////////////////////////////////////////
 // EventMark
 EventMark::EventMark(const char* format, ...) {
   if (LogEvents) {
     va_list ap;
     va_start(ap, format);
     intptr_t arg_1 = va_arg(ap, intptr_t);
     intptr_t arg_2 = va_arg(ap, intptr_t);
     intptr_t arg_3 = va_arg(ap, intptr_t);
     va_end(ap);
     EventBuffer::add_event(format, arg_1, arg_2, arg_3);
     EventBuffer::inc_indent();
   }
 }
 EventMark::~EventMark() {
   if (LogEvents) {
     EventBuffer::dec_indent();
     EventBuffer::add_event("done", 0, 0, 0);
   }
 }
 ///////////////////////////////////////////////////////////////////////////
 void eventlog_init() {
   EventBuffer::init();
 }
 int print_all_events(outputStream *st) {
   EventBuffer::print_all(st);
   return 1;
 }
 #else
 void eventlog_init() {}
 int print_all_events(outputStream *st) { return 0; }
 #endif // PRODUCT

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/utilities/events.cpp@c96030fff130 (annotated)

src/share/vm/utilities/events.cpp