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 #ifndef RUNTIME_THREADHEAPSAMPLER_HPP
27 #define RUNTIME_THREADHEAPSAMPLER_HPP
28
29 #include "memory/allocation.hpp"
30
31 class ThreadHeapSampler {
32 private:
33 size_t _bytes_until_sample;
34 // Cheap random number generator
35 static uint64_t _rnd;
36
37 void pick_next_geometric_sample();
38 void pick_next_sample(size_t overflowed_bytes = 0);
39 static int _enabled;
40 static int _sampling_interval;
41
42 // Used for assertion mode to determine if there is a path to a TLAB slow path
43 // without a collector present.
44 size_t _collectors_present;
45
46 static void init_log_table();
47
48 public:
49 ThreadHeapSampler() : _bytes_until_sample(0) {
50 _rnd = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(this));
51 if (_rnd == 0) {
52 _rnd = 1;
53 }
54
55 _collectors_present = 0;
56 }
57
58 size_t bytes_until_sample() { return _bytes_until_sample; }
59 void set_bytes_until_sample(size_t bytes) { _bytes_until_sample = bytes; }
60
61 void check_for_sampling(oop obj, size_t size_in_bytes, size_t bytes_allocated_before);
62
63 static int enabled();
64 static void enable();
65 static void disable();
66
67 static void set_sampling_interval(int sampling_interval);
68 static int get_sampling_interval();
69 };
70
71 #endif // SHARE_RUNTIME_THREADHEAPSAMPLER_HPP
|
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 #ifndef RUNTIME_THREADHEAPSAMPLER_HPP
27 #define RUNTIME_THREADHEAPSAMPLER_HPP
28
29 #include "memory/allocation.hpp"
30
31 class ThreadHeapSampler {
32 private:
33 // Statics for the fast log
34 static const int FastLogNumBits = 10;
35 static const int FastLogMask = (1 << FastLogNumBits) - 1;
36
37 size_t _bytes_until_sample;
38 // Cheap random number generator
39 static uint64_t _rnd;
40 static bool _log_table_initialized;
41
42 static double _log_table[1<<FastLogNumBits]; // Constant
43 static int _sampling_interval;
44
45 void pick_next_geometric_sample();
46 void pick_next_sample(size_t overflowed_bytes = 0);
47
48 // Used for assertion mode to determine if there is a path to a TLAB slow path
49 // without a collector present.
50 size_t _collectors_present;
51
52 static double fast_log2(const double& d);
53 static bool init_log_table();
54 uint64_t next_random(uint64_t rnd);
55
56 public:
57 ThreadHeapSampler() : _bytes_until_sample(0) {
58 _rnd = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(this));
59 if (_rnd == 0) {
60 _rnd = 1;
61 }
62
63 _collectors_present = 0;
64 }
65
66 size_t bytes_until_sample() { return _bytes_until_sample; }
67 void set_bytes_until_sample(size_t bytes) { _bytes_until_sample = bytes; }
68
69 void check_for_sampling(oop obj, size_t size_in_bytes, size_t bytes_allocated_before);
70
71 static void set_sampling_interval(int sampling_interval);
72 static int get_sampling_interval();
73 };
74
75 #endif // SHARE_RUNTIME_THREADHEAPSAMPLER_HPP
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