1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "interpreter/invocationCounter.hpp"
27
init()28 void InvocationCounter::init() {
29 _counter = 0; // reset all the bits, including the sticky carry
30 }
31
set(uint count,uint flag)32 void InvocationCounter::set(uint count, uint flag) {
33 _counter = (count << number_of_noncount_bits) | (flag & carry_mask);
34 }
35
set(uint count)36 void InvocationCounter::set(uint count) {
37 uint carry = (_counter & carry_mask); // the carry bit is sticky
38 _counter = (count << number_of_noncount_bits) | carry;
39 }
40
update(uint new_count)41 void InvocationCounter::update(uint new_count) {
42 // Don't make the method look like it's never been executed
43 uint counter = raw_counter();
44 uint c = extract_count(counter);
45 uint f = extract_carry(counter);
46 // prevent from going to zero, to distinguish from never-executed methods
47 if (c > 0 && new_count == 0) new_count = 1;
48 set(new_count, f);
49 }
50
set_carry_and_reduce()51 void InvocationCounter::set_carry_and_reduce() {
52 uint counter = raw_counter();
53 // The carry bit now indicates that this counter had achieved a very
54 // large value. Now reduce the value, so that the method can be
55 // executed many more times before re-entering the VM.
56 uint old_count = extract_count(counter);
57 uint new_count = MIN2(old_count, (uint)(CompileThreshold / 2));
58 // prevent from going to zero, to distinguish from never-executed methods
59 if (new_count == 0) new_count = 1;
60 if (old_count != new_count) set(new_count, carry_mask);
61 }
62
set_carry_on_overflow()63 void InvocationCounter::set_carry_on_overflow() {
64 if (!carry() && count() > InvocationCounter::count_limit / 2) {
65 set_carry();
66 }
67 }
68
reset()69 void InvocationCounter::reset() {
70 update(0);
71 }
72
decay()73 void InvocationCounter::decay() {
74 update(count() >> 1);
75 }
76
print()77 void InvocationCounter::print() {
78 uint counter = raw_counter();
79 tty->print_cr("invocation count: up = %d, limit = %d, carry = %s",
80 extract_count(counter), limit(),
81 extract_carry(counter) ? "true" : "false");
82 }
83