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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef NET_DISK_CACHE_BLOCKFILE_STATS_H_ | |
6 #define NET_DISK_CACHE_BLOCKFILE_STATS_H_ | |
7 | |
8 #include <string> | |
9 #include <vector> | |
10 | |
11 #include "base/basictypes.h" | |
12 #include "net/disk_cache/blockfile/addr.h" | |
13 | |
14 namespace base { | |
15 class HistogramSamples; | |
16 } // namespace base | |
17 | |
18 namespace disk_cache { | |
19 | |
20 typedef std::vector<std::pair<std::string, std::string> > StatsItems; | |
21 | |
22 // This class stores cache-specific usage information, for tunning purposes. | |
23 class Stats { | |
24 public: | |
25 static const int kDataSizesLength = 28; | |
26 enum Counters { | |
27 MIN_COUNTER = 0, | |
28 OPEN_MISS = MIN_COUNTER, | |
29 OPEN_HIT, | |
30 CREATE_MISS, | |
31 CREATE_HIT, | |
32 RESURRECT_HIT, | |
33 CREATE_ERROR, | |
34 TRIM_ENTRY, | |
35 DOOM_ENTRY, | |
36 DOOM_CACHE, | |
37 INVALID_ENTRY, | |
38 OPEN_ENTRIES, // Average number of open entries. | |
39 MAX_ENTRIES, // Maximum number of open entries. | |
40 TIMER, | |
41 READ_DATA, | |
42 WRITE_DATA, | |
43 OPEN_RANKINGS, // An entry has to be read just to modify rankings. | |
44 GET_RANKINGS, // We got the ranking info without reading the whole entry. | |
45 FATAL_ERROR, | |
46 LAST_REPORT, // Time of the last time we sent a report. | |
47 LAST_REPORT_TIMER, // Timer count of the last time we sent a report. | |
48 DOOM_RECENT, // The cache was partially cleared. | |
49 UNUSED, // Was: ga.js was evicted from the cache. | |
50 MAX_COUNTER | |
51 }; | |
52 | |
53 Stats(); | |
54 ~Stats(); | |
55 | |
56 // Initializes this object with |data| from disk. | |
57 bool Init(void* data, int num_bytes, Addr address); | |
58 | |
59 // Generates a size distribution histogram. | |
60 void InitSizeHistogram(); | |
61 | |
62 // Returns the number of bytes needed to store the stats on disk. | |
63 int StorageSize(); | |
64 | |
65 // Tracks changes to the stoage space used by an entry. | |
66 void ModifyStorageStats(int32 old_size, int32 new_size); | |
67 | |
68 // Tracks general events. | |
69 void OnEvent(Counters an_event); | |
70 void SetCounter(Counters counter, int64 value); | |
71 int64 GetCounter(Counters counter) const; | |
72 | |
73 void GetItems(StatsItems* items); | |
74 int GetHitRatio() const; | |
75 int GetResurrectRatio() const; | |
76 void ResetRatios(); | |
77 | |
78 // Returns the lower bound of the space used by entries bigger than 512 KB. | |
79 int GetLargeEntriesSize(); | |
80 | |
81 // Writes the stats into |data|, to be stored at the given cache address. | |
82 // Returns the number of bytes copied. | |
83 int SerializeStats(void* data, int num_bytes, Addr* address); | |
84 | |
85 private: | |
86 // Supports generation of SizeStats histogram data. | |
87 int GetBucketRange(size_t i) const; | |
88 int GetStatsBucket(int32 size); | |
89 int GetRatio(Counters hit, Counters miss) const; | |
90 | |
91 Addr storage_addr_; | |
92 int data_sizes_[kDataSizesLength]; | |
93 int64 counters_[MAX_COUNTER]; | |
94 | |
95 DISALLOW_COPY_AND_ASSIGN(Stats); | |
96 }; | |
97 | |
98 } // namespace disk_cache | |
99 | |
100 #endif // NET_DISK_CACHE_BLOCKFILE_STATS_H_ | |
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