< prev index next >

src/hotspot/share/runtime/threadHeapSampler.cpp

Print this page




   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"

  27 #include "runtime/handles.inline.hpp"
  28 #include "runtime/orderAccess.hpp"
  29 #include "runtime/sharedRuntime.hpp"
  30 #include "runtime/threadHeapSampler.hpp"
  31 
  32 // Cheap random number generator.
  33 uint64_t ThreadHeapSampler::_rnd;
  34 // Default is 512kb.
  35 volatile int ThreadHeapSampler::_sampling_interval = 512 * 1024;
  36 
  37 // Ordering here is important: _log_table first, _log_table_initialized second.
  38 double ThreadHeapSampler::_log_table[1 << ThreadHeapSampler::FastLogNumBits] = {};
  39 
  40 // Force initialization of the log_table.
  41 bool ThreadHeapSampler::_log_table_initialized = init_log_table();
  42 
  43 bool ThreadHeapSampler::init_log_table() {
  44   for (int i = 0; i < (1 << FastLogNumBits); i++) {
  45     _log_table[i] = (log(1.0 + static_cast<double>(i+0.5) / (1 << FastLogNumBits))
  46                     / log(2.0));
  47   }
  48   return true;




   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "runtime/atomic.hpp"
  28 #include "runtime/handles.inline.hpp"

  29 #include "runtime/sharedRuntime.hpp"
  30 #include "runtime/threadHeapSampler.hpp"
  31 
  32 // Cheap random number generator.
  33 uint64_t ThreadHeapSampler::_rnd;
  34 // Default is 512kb.
  35 volatile int ThreadHeapSampler::_sampling_interval = 512 * 1024;
  36 
  37 // Ordering here is important: _log_table first, _log_table_initialized second.
  38 double ThreadHeapSampler::_log_table[1 << ThreadHeapSampler::FastLogNumBits] = {};
  39 
  40 // Force initialization of the log_table.
  41 bool ThreadHeapSampler::_log_table_initialized = init_log_table();
  42 
  43 bool ThreadHeapSampler::init_log_table() {
  44   for (int i = 0; i < (1 << FastLogNumBits); i++) {
  45     _log_table[i] = (log(1.0 + static_cast<double>(i+0.5) / (1 << FastLogNumBits))
  46                     / log(2.0));
  47   }
  48   return true;


< prev index next >