6711316: Open source the Garbage-First garbage collector
Summary: First mercurial integration of the code for the Garbage-First garbage collector.
Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, 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.
*
*/
# include "incls/_precompiled.incl"
# include "incls/_coTracker.cpp.incl"
COTracker* COTracker::_head = NULL;
double COTracker::_cpu_number = -1.0;
void
COTracker::resetPeriod(double now_sec, double vnow_sec) {
guarantee( _enabled, "invariant" );
_period_start_time_sec = now_sec;
_period_start_vtime_sec = vnow_sec;
}
void
COTracker::setConcOverhead(double time_stamp_sec,
double conc_overhead) {
guarantee( _enabled, "invariant" );
_conc_overhead = conc_overhead;
_time_stamp_sec = time_stamp_sec;
if (conc_overhead > 0.001)
_conc_overhead_seq.add(conc_overhead);
}
void
COTracker::reset(double starting_conc_overhead) {
guarantee( _enabled, "invariant" );
double now_sec = os::elapsedTime();
setConcOverhead(now_sec, starting_conc_overhead);
}
void
COTracker::start() {
guarantee( _enabled, "invariant" );
resetPeriod(os::elapsedTime(), os::elapsedVTime());
}
void
COTracker::update(bool force_end) {
assert( _enabled, "invariant" );
double end_time_sec = os::elapsedTime();
double elapsed_time_sec = end_time_sec - _period_start_time_sec;
if (force_end || elapsed_time_sec > _update_period_sec) {
// reached the end of the period
double end_vtime_sec = os::elapsedVTime();
double elapsed_vtime_sec = end_vtime_sec - _period_start_vtime_sec;
double conc_overhead = elapsed_vtime_sec / elapsed_time_sec;
setConcOverhead(end_time_sec, conc_overhead);
resetPeriod(end_time_sec, end_vtime_sec);
}
}
void
COTracker::updateForSTW(double start_sec, double end_sec) {
if (!_enabled)
return;
// During a STW pause, no concurrent GC thread has done any
// work. So, we can safely adjust the start of the current period by
// adding the duration of the STW pause to it, so that the STW pause
// doesn't affect the reading of the concurrent overhead (it's
// basically like excluding the time of the STW pause from the
// concurrent overhead calculation).
double stw_duration_sec = end_sec - start_sec;
guarantee( stw_duration_sec > 0.0, "invariant" );
if (outOfDate(start_sec))
_conc_overhead = 0.0;
else
_time_stamp_sec = end_sec;
_period_start_time_sec += stw_duration_sec;
_conc_overhead_seq = NumberSeq();
guarantee( os::elapsedTime() > _period_start_time_sec, "invariant" );
}
double
COTracker::predConcOverhead() {
if (_enabled) {
// tty->print(" %1.2lf", _conc_overhead_seq.maximum());
return _conc_overhead_seq.maximum();
} else {
// tty->print(" DD");
return 0.0;
}
}
void
COTracker::resetPred() {
_conc_overhead_seq = NumberSeq();
}
COTracker::COTracker(int group)
: _enabled(false),
_group(group),
_period_start_time_sec(-1.0),
_period_start_vtime_sec(-1.0),
_conc_overhead(-1.0),
_time_stamp_sec(-1.0),
_next(NULL) {
// GCOverheadReportingPeriodMS indicates how frequently the
// concurrent overhead will be recorded by the GC Overhead
// Reporter. We want to take readings less often than that. If we
// took readings more often than some of them might be lost.
_update_period_sec = ((double) GCOverheadReportingPeriodMS) / 1000.0 * 1.25;
_next = _head;
_head = this;
if (_cpu_number < 0.0)
_cpu_number = (double) os::processor_count();
}
// statics
void
COTracker::updateAllForSTW(double start_sec, double end_sec) {
for (COTracker* curr = _head; curr != NULL; curr = curr->_next) {
curr->updateForSTW(start_sec, end_sec);
}
}
double
COTracker::totalConcOverhead(double now_sec) {
double total_conc_overhead = 0.0;
for (COTracker* curr = _head; curr != NULL; curr = curr->_next) {
double conc_overhead = curr->concOverhead(now_sec);
total_conc_overhead += conc_overhead;
}
return total_conc_overhead;
}
double
COTracker::totalConcOverhead(double now_sec,
size_t group_num,
double* co_per_group) {
double total_conc_overhead = 0.0;
for (size_t i = 0; i < group_num; ++i)
co_per_group[i] = 0.0;
for (COTracker* curr = _head; curr != NULL; curr = curr->_next) {
size_t group = curr->_group;
assert( 0 <= group && group < group_num, "invariant" );
double conc_overhead = curr->concOverhead(now_sec);
co_per_group[group] += conc_overhead;
total_conc_overhead += conc_overhead;
}
return total_conc_overhead;
}
double
COTracker::totalPredConcOverhead() {
double total_pred_conc_overhead = 0.0;
for (COTracker* curr = _head; curr != NULL; curr = curr->_next) {
total_pred_conc_overhead += curr->predConcOverhead();
curr->resetPred();
}
return total_pred_conc_overhead / _cpu_number;
}