Mercurial > hg > truffle
annotate src/share/vm/utilities/intHisto.hpp @ 20543:e7d0505c8a30
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
| author | tschatzl |
|---|---|
| date | Fri, 10 Oct 2014 15:51:58 +0200 |
| parents | b9a9ed0f8eeb |
| children |
| rev | line source |
|---|---|
| 342 | 1 /* |
|
6842
b9a9ed0f8eeb
7197424: update copyright year to match last edit in jdk8 hotspot repository
mikael
parents:
6197
diff
changeset
|
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. |
| 342 | 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 * | |
|
1552
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
342
diff
changeset
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
342
diff
changeset
|
20 * or visit www.oracle.com if you need additional information or have any |
|
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
342
diff
changeset
|
21 * questions. |
| 342 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #ifndef SHARE_VM_UTILITIES_INTHISTO_HPP |
| 26 #define SHARE_VM_UTILITIES_INTHISTO_HPP | |
| 27 | |
| 28 #include "memory/allocation.hpp" | |
| 29 #include "utilities/growableArray.hpp" | |
| 30 | |
| 342 | 31 // This class implements a simple histogram. |
| 32 | |
| 33 // A histogram summarizes a series of "measurements", each of which is | |
| 34 // assumed (required in this implementation) to have an outcome that is a | |
| 35 // non-negative integer. The histogram efficiently maps measurement outcomes | |
| 36 // to the number of measurements had that outcome. | |
| 37 | |
| 38 // To print the results, invoke print() on your Histogram*. | |
| 39 | |
| 40 // Note: there is already an existing "Histogram" class, in file | |
| 41 // histogram.{hpp,cpp}, but to my mind that's not a histogram, it's a table | |
| 42 // mapping strings to counts. To be a histogram (IMHO) it needs to map | |
| 43 // numbers (in fact, integers) to number of occurrences of that number. | |
| 44 | |
| 45 // ysr: (i am not sure i agree with the above note.) i suspect we want to have a | |
| 46 // histogram template that will map an arbitrary type (with a defined order | |
| 47 // relation) to a count. | |
| 48 | |
| 49 | |
| 6197 | 50 class IntHistogram : public CHeapObj<mtInternal> { |
| 342 | 51 protected: |
| 52 int _max; | |
| 53 int _tot; | |
| 54 GrowableArray<int>* _elements; | |
| 55 | |
| 56 public: | |
| 57 // Create a new, empty table. "est" is an estimate of the maximum outcome | |
| 58 // that will be added, and "max" is an outcome such that all outcomes at | |
| 59 // least that large will be bundled with it. | |
| 60 IntHistogram(int est, int max); | |
| 61 // Add a measurement with the given outcome to the sequence. | |
| 62 void add_entry(int outcome); | |
| 63 // Return the number of entries recorded so far with the given outcome. | |
| 64 int entries_for_outcome(int outcome); | |
| 65 // Return the total number of entries recorded so far. | |
| 66 int total_entries() { return _tot; } | |
| 67 // Return the number of entries recorded so far with the given outcome as | |
| 68 // a fraction of the total number recorded so far. | |
| 69 double fraction_for_outcome(int outcome) { | |
| 70 return | |
| 71 (double)entries_for_outcome(outcome)/ | |
| 72 (double)total_entries(); | |
| 73 } | |
| 74 // Print the histogram on the given output stream. | |
| 75 void print_on(outputStream* st) const; | |
| 76 }; | |
| 1972 | 77 |
| 78 #endif // SHARE_VM_UTILITIES_INTHISTO_HPP |