Fri, 22 Feb 2008 17:17:14 -0800
6362677: Change parallel GC collector default number of parallel GC threads.
Summary: Use the same default number of GC threads as used by ParNewGC and ConcMarkSweepGC (i.e., the 5/8th rule).
Reviewed-by: ysr, tonyp
1 /*
2 * Copyright 1997-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 class VM_Version: public Abstract_VM_Version {
26 protected:
27 enum Feature_Flag {
28 v8_instructions = 0,
29 hardware_int_muldiv = 1,
30 hardware_fsmuld = 2,
31 v9_instructions = 3,
32 vis1_instructions = 4,
33 vis2_instructions = 5,
34 sun4v_instructions = 6
35 };
37 enum Feature_Flag_Set {
38 unknown_m = 0,
39 all_features_m = -1,
41 v8_instructions_m = 1 << v8_instructions,
42 hardware_int_muldiv_m = 1 << hardware_int_muldiv,
43 hardware_fsmuld_m = 1 << hardware_fsmuld,
44 v9_instructions_m = 1 << v9_instructions,
45 vis1_instructions_m = 1 << vis1_instructions,
46 vis2_instructions_m = 1 << vis2_instructions,
47 sun4v_m = 1 << sun4v_instructions,
49 generic_v8_m = v8_instructions_m | hardware_int_muldiv_m | hardware_fsmuld_m,
50 generic_v9_m = generic_v8_m | v9_instructions_m | vis1_instructions_m,
51 ultra3_m = generic_v9_m | vis2_instructions_m,
53 // Temporary until we have something more accurate
54 niagara1_unique_m = sun4v_m,
55 niagara1_m = generic_v9_m | niagara1_unique_m
56 };
58 static int _features;
59 static const char* _features_str;
61 static void print_features();
62 static int determine_features();
63 static int platform_features(int features);
65 static bool is_niagara1(int features) { return (features & niagara1_m) == niagara1_m; }
67 static int maximum_niagara1_processor_count() { return 32; }
68 // Returns true if the platform is in the niagara line and
69 // newer than the niagara1.
70 static bool is_niagara1_plus();
72 public:
73 // Initialization
74 static void initialize();
76 // Instruction support
77 static bool has_v8() { return (_features & v8_instructions_m) != 0; }
78 static bool has_v9() { return (_features & v9_instructions_m) != 0; }
79 static bool has_hardware_int_muldiv() { return (_features & hardware_int_muldiv_m) != 0; }
80 static bool has_hardware_fsmuld() { return (_features & hardware_fsmuld_m) != 0; }
81 static bool has_vis1() { return (_features & vis1_instructions_m) != 0; }
82 static bool has_vis2() { return (_features & vis2_instructions_m) != 0; }
84 static bool supports_compare_and_exchange()
85 { return has_v9(); }
87 static bool is_ultra3() { return (_features & ultra3_m) == ultra3_m; }
88 static bool is_sun4v() { return (_features & sun4v_m) != 0; }
89 static bool is_niagara1() { return is_niagara1(_features); }
91 static bool has_fast_fxtof() { return has_v9() && !is_ultra3(); }
93 static const char* cpu_features() { return _features_str; }
95 static intx L1_data_cache_line_size() {
96 return 64; // default prefetch block size on sparc
97 }
99 // Prefetch
100 static intx prefetch_copy_interval_in_bytes() {
101 intx interval = PrefetchCopyIntervalInBytes;
102 return interval >= 0 ? interval : (has_v9() ? 512 : 0);
103 }
104 static intx prefetch_scan_interval_in_bytes() {
105 intx interval = PrefetchScanIntervalInBytes;
106 return interval >= 0 ? interval : (has_v9() ? 512 : 0);
107 }
108 static intx prefetch_fields_ahead() {
109 intx count = PrefetchFieldsAhead;
110 return count >= 0 ? count : (is_ultra3() ? 1 : 0);
111 }
113 static intx allocate_prefetch_distance() {
114 // This method should be called before allocate_prefetch_style().
115 intx count = AllocatePrefetchDistance;
116 if (count < 0) { // default is not defined ?
117 count = 512;
118 }
119 return count;
120 }
121 static intx allocate_prefetch_style() {
122 assert(AllocatePrefetchStyle >= 0, "AllocatePrefetchStyle should be positive");
123 // Return 0 if AllocatePrefetchDistance was not defined.
124 return AllocatePrefetchDistance > 0 ? AllocatePrefetchStyle : 0;
125 }
127 // Legacy
128 static bool v8_instructions_work() { return has_v8() && !has_v9(); }
129 static bool v9_instructions_work() { return has_v9(); }
131 // Assembler testing
132 static void allow_all();
133 static void revert();
135 // Override the Abstract_VM_Version implementation.
136 static uint page_size_count() { return is_sun4v() ? 4 : 2; }
138 // Calculates the number of parallel threads
139 static unsigned int calc_parallel_worker_threads();
140 };