jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/shared/coTracker.hpp@06df86c2ec37 (annotated)

src/share/vm/gc_implementation/shared/coTracker.hpp@06df86c2ec37 (annotated)

src/share/vm/gc_implementation/shared/coTracker.hpp

Sat, 27 Sep 2008 00:33:13 -0700

author: iveresov
date: Sat, 27 Sep 2008 00:33:13 -0700
changeset 808: 06df86c2ec37
parent 777: 37f87013dfd8
permissions: -rw-r--r--

6740923: NUMA allocator: Ensure the progress of adaptive chunk resizing
Summary: Treat a chuck where the allocation has failed as fully used.
Reviewed-by: ysr

 /*
  * Copyright 2001-2007 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.
  *
  */
 // COTracker keeps track of the concurrent overhead of a GC thread.
 // A thread that needs to be tracked must, itself, start up its
 // tracker with the start() method and then call the update() method
 // at regular intervals. What the tracker does is to calculate the
 // concurrent overhead of a process at a given update period. The
 // tracker starts and when is detects that it has exceeded the given
 // period, it calculates the duration of the period in wall-clock time
 // and the duration of the period in vtime (i.e. how much time the
 // concurrent processes really took up during this period). The ratio
 // of the latter over the former is the concurrent overhead of that
 // process for that period over a single CPU. This overhead is stored
 // on the tracker, "timestamped" with the wall-clock time of the end
 // of the period. When the concurrent overhead of this process needs
 // to be queried, this last "reading" provides a good approximation
 // (we assume that the concurrent overhead of a particular thread
 // stays largely constant over time). The timestamp is necessary to
 // detect when the process has stopped working and the recorded
 // reading hasn't been updated for some time.
 // Each concurrent GC thread is considered to be part of a "group"
 // (i.e. any available concurrent marking threads are part of the
 // "concurrent marking thread group"). A COTracker is associated with
 // a single group at construction-time. It's up to each collector to
 // decide how groups will be mapped to such an id (ids should start
 // from 0 and be consecutive; there's a hardcoded max group num
 // defined on the GCOverheadTracker class). The notion of a group has
 // been introduced to be able to identify how much overhead was
 // imposed by each group, instead of getting a single value that
 // covers all concurrent overhead.
 class COTracker {
 private:
   // It indicates whether this tracker is enabled or not. When the
   // tracker is disabled, then it returns 0.0 as the latest concurrent
   // overhead and several methods (reset, start, and update) are not
   // supposed to be called on it. This enabling / disabling facility
   // is really provided to make a bit more explicit in the code when a
   // particulary tracker of a processes that doesn't run all the time
   // (e.g. concurrent marking) is supposed to be used and not it's not.
   bool               _enabled;
   // The ID of the group associated with this tracker.
   int                _group;
   // The update period of the tracker. A new value for the concurrent
   // overhead of the associated process will be made at intervals no
   // smaller than this.
   double             _update_period_sec;
   // The start times (both wall-block time and vtime) of the current
   // interval.
   double             _period_start_time_sec;
   double             _period_start_vtime_sec;
   // Number seq of the concurrent overhead readings within a period
   NumberSeq          _conc_overhead_seq;
   // The latest reading of the concurrent overhead (over a single CPU)
   // imposed by the associated concurrent thread, made available at
   // the indicated wall-clock time.
   double             _conc_overhead;
   double             _time_stamp_sec;
   // The number of CPUs that the host machine has (for convenience
   // really, as we'd have to keep translating it into a double)
   static double      _cpu_number;
   // Fields that keep a list of all trackers created. This is useful,
   // since it allows us to sum up the concurrent overhead without
   // having to write code for a specific collector to broadcast a
   // request to all its concurrent processes.
   COTracker*         _next;
   static COTracker*  _head;
   // It indicates that a new period is starting by updating the
   // _period_start_time_sec and _period_start_vtime_sec fields.
   void resetPeriod(double now_sec, double vnow_sec);
   // It updates the latest concurrent overhead reading, taken at a
   // given wall-clock time.
   void setConcOverhead(double time_stamp_sec, double conc_overhead);
   // It determines whether the time stamp of the latest concurrent
   // overhead reading is out of date or not.
   bool outOfDate(double now_sec) {
     // The latest reading is considered out of date, if it was taken
     // 1.2x the update period.
     return (now_sec - _time_stamp_sec) > 1.2 * _update_period_sec;
   }
 public:
   // The constructor which associates the tracker with a group ID.
   COTracker(int group);
   // Methods to enable / disable the tracker and query whether it is enabled.
   void enable()  { _enabled = true;  }
   void disable() { _enabled = false; }
   bool enabled() { return _enabled;  }
   // It resets the tracker and sets concurrent overhead reading to be
   // the given parameter and the associated time stamp to be now.
   void reset(double starting_conc_overhead = 0.0);
   // The tracker starts tracking. IT should only be called from the
   // concurrent thread that is tracked by this tracker.
   void start();
   // It updates the tracker and, if the current period is longer than
   // the update period, the concurrent overhead reading will be
   // updated. force_end being true indicates that it's the last call
   // to update() by this process before the tracker is disabled (the
   // tracker can be re-enabled later if necessary).  It should only be
   // called from the concurrent thread that is tracked by this tracker
   // and while the thread has joined the STS.
   void update(bool force_end = false);
   // It adjusts the contents of the tracker to take into account a STW
   // pause.
   void updateForSTW(double start_sec, double end_sec);
   // It returns the last concurrent overhead reading over a single
   // CPU. If the reading is out of date, or the tracker is disabled,
   // it returns 0.0.
   double concCPUOverhead(double now_sec) {
     if (!_enabled || outOfDate(now_sec))
       return 0.0;
     else
       return _conc_overhead;
   }
   // It returns the last concurrent overhead reading over all CPUs
   // that the host machine has. If the reading is out of date, or the
   // tracker is disabled, it returns 0.0.
   double concOverhead(double now_sec) {
     return concCPUOverhead(now_sec) / _cpu_number;
   }
   double predConcOverhead();
   void resetPred();
   // statics
   // It notifies all trackers about a STW pause.
   static void updateAllForSTW(double start_sec, double end_sec);
   // It returns the sum of the concurrent overhead readings of all
   // available (and enabled) trackers for the given time stamp. The
   // overhead is over all the CPUs of the host machine.
   static double totalConcOverhead(double now_sec);
   // Like the previous method, but it also sums up the overheads per
   // group number. The length of the co_per_group array must be at
   // least as large group_num
   static double totalConcOverhead(double now_sec,
                                   size_t group_num,
                                   double* co_per_group);
   static double totalPredConcOverhead();
 };

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/shared/coTracker.hpp@06df86c2ec37 (annotated)

src/share/vm/gc_implementation/shared/coTracker.hpp