Fri, 10 Oct 2014 15:51:58 +0200
8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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13 * accompanied this code).
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1StringDedupStat.hpp"
28 G1StringDedupStat::G1StringDedupStat() :
29 _inspected(0),
30 _skipped(0),
31 _hashed(0),
32 _known(0),
33 _new(0),
34 _new_bytes(0),
35 _deduped(0),
36 _deduped_bytes(0),
37 _deduped_young(0),
38 _deduped_young_bytes(0),
39 _deduped_old(0),
40 _deduped_old_bytes(0),
41 _idle(0),
42 _exec(0),
43 _block(0),
44 _start(0.0),
45 _idle_elapsed(0.0),
46 _exec_elapsed(0.0),
47 _block_elapsed(0.0) {
48 }
50 void G1StringDedupStat::add(const G1StringDedupStat& stat) {
51 _inspected += stat._inspected;
52 _skipped += stat._skipped;
53 _hashed += stat._hashed;
54 _known += stat._known;
55 _new += stat._new;
56 _new_bytes += stat._new_bytes;
57 _deduped += stat._deduped;
58 _deduped_bytes += stat._deduped_bytes;
59 _deduped_young += stat._deduped_young;
60 _deduped_young_bytes += stat._deduped_young_bytes;
61 _deduped_old += stat._deduped_old;
62 _deduped_old_bytes += stat._deduped_old_bytes;
63 _idle += stat._idle;
64 _exec += stat._exec;
65 _block += stat._block;
66 _idle_elapsed += stat._idle_elapsed;
67 _exec_elapsed += stat._exec_elapsed;
68 _block_elapsed += stat._block_elapsed;
69 }
71 void G1StringDedupStat::print_summary(outputStream* st, const G1StringDedupStat& last_stat, const G1StringDedupStat& total_stat) {
72 double total_deduped_bytes_percent = 0.0;
74 if (total_stat._new_bytes > 0) {
75 // Avoid division by zero
76 total_deduped_bytes_percent = (double)total_stat._deduped_bytes / (double)total_stat._new_bytes * 100.0;
77 }
79 st->date_stamp(PrintGCDateStamps);
80 st->stamp(PrintGCTimeStamps);
81 st->print_cr(
82 "[GC concurrent-string-deduplication, "
83 G1_STRDEDUP_BYTES_FORMAT_NS"->"G1_STRDEDUP_BYTES_FORMAT_NS"("G1_STRDEDUP_BYTES_FORMAT_NS"), avg "
84 G1_STRDEDUP_PERCENT_FORMAT_NS", "G1_STRDEDUP_TIME_FORMAT"]",
85 G1_STRDEDUP_BYTES_PARAM(last_stat._new_bytes),
86 G1_STRDEDUP_BYTES_PARAM(last_stat._new_bytes - last_stat._deduped_bytes),
87 G1_STRDEDUP_BYTES_PARAM(last_stat._deduped_bytes),
88 total_deduped_bytes_percent,
89 last_stat._exec_elapsed);
90 }
92 void G1StringDedupStat::print_statistics(outputStream* st, const G1StringDedupStat& stat, bool total) {
93 double young_percent = 0.0;
94 double old_percent = 0.0;
95 double skipped_percent = 0.0;
96 double hashed_percent = 0.0;
97 double known_percent = 0.0;
98 double new_percent = 0.0;
99 double deduped_percent = 0.0;
100 double deduped_bytes_percent = 0.0;
101 double deduped_young_percent = 0.0;
102 double deduped_young_bytes_percent = 0.0;
103 double deduped_old_percent = 0.0;
104 double deduped_old_bytes_percent = 0.0;
106 if (stat._inspected > 0) {
107 // Avoid division by zero
108 skipped_percent = (double)stat._skipped / (double)stat._inspected * 100.0;
109 hashed_percent = (double)stat._hashed / (double)stat._inspected * 100.0;
110 known_percent = (double)stat._known / (double)stat._inspected * 100.0;
111 new_percent = (double)stat._new / (double)stat._inspected * 100.0;
112 }
114 if (stat._new > 0) {
115 // Avoid division by zero
116 deduped_percent = (double)stat._deduped / (double)stat._new * 100.0;
117 }
119 if (stat._deduped > 0) {
120 // Avoid division by zero
121 deduped_young_percent = (double)stat._deduped_young / (double)stat._deduped * 100.0;
122 deduped_old_percent = (double)stat._deduped_old / (double)stat._deduped * 100.0;
123 }
125 if (stat._new_bytes > 0) {
126 // Avoid division by zero
127 deduped_bytes_percent = (double)stat._deduped_bytes / (double)stat._new_bytes * 100.0;
128 }
130 if (stat._deduped_bytes > 0) {
131 // Avoid division by zero
132 deduped_young_bytes_percent = (double)stat._deduped_young_bytes / (double)stat._deduped_bytes * 100.0;
133 deduped_old_bytes_percent = (double)stat._deduped_old_bytes / (double)stat._deduped_bytes * 100.0;
134 }
136 if (total) {
137 st->print_cr(
138 " [Total Exec: "UINTX_FORMAT"/"G1_STRDEDUP_TIME_FORMAT", Idle: "UINTX_FORMAT"/"G1_STRDEDUP_TIME_FORMAT", Blocked: "UINTX_FORMAT"/"G1_STRDEDUP_TIME_FORMAT"]",
139 stat._exec, stat._exec_elapsed, stat._idle, stat._idle_elapsed, stat._block, stat._block_elapsed);
140 } else {
141 st->print_cr(
142 " [Last Exec: "G1_STRDEDUP_TIME_FORMAT", Idle: "G1_STRDEDUP_TIME_FORMAT", Blocked: "UINTX_FORMAT"/"G1_STRDEDUP_TIME_FORMAT"]",
143 stat._exec_elapsed, stat._idle_elapsed, stat._block, stat._block_elapsed);
144 }
145 st->print_cr(
146 " [Inspected: "G1_STRDEDUP_OBJECTS_FORMAT"]\n"
147 " [Skipped: "G1_STRDEDUP_OBJECTS_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT")]\n"
148 " [Hashed: "G1_STRDEDUP_OBJECTS_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT")]\n"
149 " [Known: "G1_STRDEDUP_OBJECTS_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT")]\n"
150 " [New: "G1_STRDEDUP_OBJECTS_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT") "G1_STRDEDUP_BYTES_FORMAT"]\n"
151 " [Deduplicated: "G1_STRDEDUP_OBJECTS_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT") "G1_STRDEDUP_BYTES_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT")]\n"
152 " [Young: "G1_STRDEDUP_OBJECTS_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT") "G1_STRDEDUP_BYTES_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT")]\n"
153 " [Old: "G1_STRDEDUP_OBJECTS_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT") "G1_STRDEDUP_BYTES_FORMAT"("G1_STRDEDUP_PERCENT_FORMAT")]",
154 stat._inspected,
155 stat._skipped, skipped_percent,
156 stat._hashed, hashed_percent,
157 stat._known, known_percent,
158 stat._new, new_percent, G1_STRDEDUP_BYTES_PARAM(stat._new_bytes),
159 stat._deduped, deduped_percent, G1_STRDEDUP_BYTES_PARAM(stat._deduped_bytes), deduped_bytes_percent,
160 stat._deduped_young, deduped_young_percent, G1_STRDEDUP_BYTES_PARAM(stat._deduped_young_bytes), deduped_young_bytes_percent,
161 stat._deduped_old, deduped_old_percent, G1_STRDEDUP_BYTES_PARAM(stat._deduped_old_bytes), deduped_old_bytes_percent);
162 }