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1 // Copyright (c) 2011 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 #include "net/disk_cache/blockfile/stats.h" | |
6 | |
7 #include "base/format_macros.h" | |
8 #include "base/logging.h" | |
9 #include "base/metrics/bucket_ranges.h" | |
10 #include "base/metrics/histogram.h" | |
11 #include "base/metrics/histogram_samples.h" | |
12 #include "base/metrics/sample_vector.h" | |
13 #include "base/metrics/statistics_recorder.h" | |
14 #include "base/strings/string_util.h" | |
15 #include "base/strings/stringprintf.h" | |
16 | |
17 namespace { | |
18 | |
19 const int32 kDiskSignature = 0xF01427E0; | |
20 | |
21 struct OnDiskStats { | |
22 int32 signature; | |
23 int size; | |
24 int data_sizes[disk_cache::Stats::kDataSizesLength]; | |
25 int64 counters[disk_cache::Stats::MAX_COUNTER]; | |
26 }; | |
27 static_assert(sizeof(OnDiskStats) < 512, "needs more than 2 blocks"); | |
28 | |
29 // Returns the "floor" (as opposed to "ceiling") of log base 2 of number. | |
30 int LogBase2(int32 number) { | |
31 unsigned int value = static_cast<unsigned int>(number); | |
32 const unsigned int mask[] = {0x2, 0xC, 0xF0, 0xFF00, 0xFFFF0000}; | |
33 const unsigned int s[] = {1, 2, 4, 8, 16}; | |
34 | |
35 unsigned int result = 0; | |
36 for (int i = 4; i >= 0; i--) { | |
37 if (value & mask[i]) { | |
38 value >>= s[i]; | |
39 result |= s[i]; | |
40 } | |
41 } | |
42 return static_cast<int>(result); | |
43 } | |
44 | |
45 // WARNING: Add new stats only at the end, or change LoadStats(). | |
46 const char* const kCounterNames[] = { | |
47 "Open miss", | |
48 "Open hit", | |
49 "Create miss", | |
50 "Create hit", | |
51 "Resurrect hit", | |
52 "Create error", | |
53 "Trim entry", | |
54 "Doom entry", | |
55 "Doom cache", | |
56 "Invalid entry", | |
57 "Open entries", | |
58 "Max entries", | |
59 "Timer", | |
60 "Read data", | |
61 "Write data", | |
62 "Open rankings", | |
63 "Get rankings", | |
64 "Fatal error", | |
65 "Last report", | |
66 "Last report timer", | |
67 "Doom recent entries", | |
68 "unused" | |
69 }; | |
70 static_assert(arraysize(kCounterNames) == disk_cache::Stats::MAX_COUNTER, | |
71 "update the names"); | |
72 | |
73 } // namespace | |
74 | |
75 namespace disk_cache { | |
76 | |
77 bool VerifyStats(OnDiskStats* stats) { | |
78 if (stats->signature != kDiskSignature) | |
79 return false; | |
80 | |
81 // We don't want to discard the whole cache every time we have one extra | |
82 // counter; we keep old data if we can. | |
83 if (static_cast<unsigned int>(stats->size) > sizeof(*stats)) { | |
84 memset(stats, 0, sizeof(*stats)); | |
85 stats->signature = kDiskSignature; | |
86 } else if (static_cast<unsigned int>(stats->size) != sizeof(*stats)) { | |
87 size_t delta = sizeof(*stats) - static_cast<unsigned int>(stats->size); | |
88 memset(reinterpret_cast<char*>(stats) + stats->size, 0, delta); | |
89 stats->size = sizeof(*stats); | |
90 } | |
91 | |
92 return true; | |
93 } | |
94 | |
95 Stats::Stats() { | |
96 } | |
97 | |
98 Stats::~Stats() { | |
99 } | |
100 | |
101 bool Stats::Init(void* data, int num_bytes, Addr address) { | |
102 OnDiskStats local_stats; | |
103 OnDiskStats* stats = &local_stats; | |
104 if (!num_bytes) { | |
105 memset(stats, 0, sizeof(local_stats)); | |
106 local_stats.signature = kDiskSignature; | |
107 local_stats.size = sizeof(local_stats); | |
108 } else if (num_bytes >= static_cast<int>(sizeof(*stats))) { | |
109 stats = reinterpret_cast<OnDiskStats*>(data); | |
110 if (!VerifyStats(stats)) | |
111 return false; | |
112 } else { | |
113 return false; | |
114 } | |
115 | |
116 storage_addr_ = address; | |
117 | |
118 memcpy(data_sizes_, stats->data_sizes, sizeof(data_sizes_)); | |
119 memcpy(counters_, stats->counters, sizeof(counters_)); | |
120 | |
121 // Clean up old value. | |
122 SetCounter(UNUSED, 0); | |
123 return true; | |
124 } | |
125 | |
126 void Stats::InitSizeHistogram() { | |
127 // Only generate this histogram for the main cache. | |
128 static bool first_time = true; | |
129 if (!first_time) | |
130 return; | |
131 | |
132 first_time = false; | |
133 int min = 1; | |
134 int max = 64 * 1024; | |
135 int num_buckets = 75; | |
136 base::BucketRanges ranges(num_buckets + 1); | |
137 base::Histogram::InitializeBucketRanges(min, max, &ranges); | |
138 | |
139 base::HistogramBase* stats_histogram = base::Histogram::FactoryGet( | |
140 "DiskCache.SizeStats2", min, max, num_buckets, | |
141 base::HistogramBase::kUmaTargetedHistogramFlag); | |
142 | |
143 base::SampleVector samples(&ranges); | |
144 for (int i = 0; i < kDataSizesLength; i++) { | |
145 // This is a good time to fix any inconsistent data. The count should be | |
146 // always positive, but if it's not, reset the value now. | |
147 if (data_sizes_[i] < 0) | |
148 data_sizes_[i] = 0; | |
149 | |
150 samples.Accumulate(GetBucketRange(i) / 1024, data_sizes_[i]); | |
151 } | |
152 stats_histogram->AddSamples(samples); | |
153 } | |
154 | |
155 int Stats::StorageSize() { | |
156 // If we have more than 512 bytes of counters, change kDiskSignature so we | |
157 // don't overwrite something else (LoadStats must fail). | |
158 static_assert(sizeof(OnDiskStats) <= 256 * 2, "use more blocks"); | |
159 return 256 * 2; | |
160 } | |
161 | |
162 void Stats::ModifyStorageStats(int32 old_size, int32 new_size) { | |
163 // We keep a counter of the data block size on an array where each entry is | |
164 // the adjusted log base 2 of the size. The first entry counts blocks of 256 | |
165 // bytes, the second blocks up to 512 bytes, etc. With 20 entries, the last | |
166 // one stores entries of more than 64 MB | |
167 int new_index = GetStatsBucket(new_size); | |
168 int old_index = GetStatsBucket(old_size); | |
169 | |
170 if (new_size) | |
171 data_sizes_[new_index]++; | |
172 | |
173 if (old_size) | |
174 data_sizes_[old_index]--; | |
175 } | |
176 | |
177 void Stats::OnEvent(Counters an_event) { | |
178 DCHECK(an_event >= MIN_COUNTER && an_event < MAX_COUNTER); | |
179 counters_[an_event]++; | |
180 } | |
181 | |
182 void Stats::SetCounter(Counters counter, int64 value) { | |
183 DCHECK(counter >= MIN_COUNTER && counter < MAX_COUNTER); | |
184 counters_[counter] = value; | |
185 } | |
186 | |
187 int64 Stats::GetCounter(Counters counter) const { | |
188 DCHECK(counter >= MIN_COUNTER && counter < MAX_COUNTER); | |
189 return counters_[counter]; | |
190 } | |
191 | |
192 void Stats::GetItems(StatsItems* items) { | |
193 std::pair<std::string, std::string> item; | |
194 for (int i = 0; i < kDataSizesLength; i++) { | |
195 item.first = base::StringPrintf("Size%02d", i); | |
196 item.second = base::StringPrintf("0x%08x", data_sizes_[i]); | |
197 items->push_back(item); | |
198 } | |
199 | |
200 for (int i = MIN_COUNTER; i < MAX_COUNTER; i++) { | |
201 item.first = kCounterNames[i]; | |
202 item.second = base::StringPrintf("0x%" PRIx64, counters_[i]); | |
203 items->push_back(item); | |
204 } | |
205 } | |
206 | |
207 int Stats::GetHitRatio() const { | |
208 return GetRatio(OPEN_HIT, OPEN_MISS); | |
209 } | |
210 | |
211 int Stats::GetResurrectRatio() const { | |
212 return GetRatio(RESURRECT_HIT, CREATE_HIT); | |
213 } | |
214 | |
215 void Stats::ResetRatios() { | |
216 SetCounter(OPEN_HIT, 0); | |
217 SetCounter(OPEN_MISS, 0); | |
218 SetCounter(RESURRECT_HIT, 0); | |
219 SetCounter(CREATE_HIT, 0); | |
220 } | |
221 | |
222 int Stats::GetLargeEntriesSize() { | |
223 int total = 0; | |
224 // data_sizes_[20] stores values between 512 KB and 1 MB (see comment before | |
225 // GetStatsBucket()). | |
226 for (int bucket = 20; bucket < kDataSizesLength; bucket++) | |
227 total += data_sizes_[bucket] * GetBucketRange(bucket); | |
228 | |
229 return total; | |
230 } | |
231 | |
232 int Stats::SerializeStats(void* data, int num_bytes, Addr* address) { | |
233 OnDiskStats* stats = reinterpret_cast<OnDiskStats*>(data); | |
234 if (num_bytes < static_cast<int>(sizeof(*stats))) | |
235 return 0; | |
236 | |
237 stats->signature = kDiskSignature; | |
238 stats->size = sizeof(*stats); | |
239 memcpy(stats->data_sizes, data_sizes_, sizeof(data_sizes_)); | |
240 memcpy(stats->counters, counters_, sizeof(counters_)); | |
241 | |
242 *address = storage_addr_; | |
243 return sizeof(*stats); | |
244 } | |
245 | |
246 int Stats::GetBucketRange(size_t i) const { | |
247 if (i < 2) | |
248 return static_cast<int>(1024 * i); | |
249 | |
250 if (i < 12) | |
251 return static_cast<int>(2048 * (i - 1)); | |
252 | |
253 if (i < 17) | |
254 return static_cast<int>(4096 * (i - 11)) + 20 * 1024; | |
255 | |
256 int n = 64 * 1024; | |
257 if (i > static_cast<size_t>(kDataSizesLength)) { | |
258 NOTREACHED(); | |
259 i = kDataSizesLength; | |
260 } | |
261 | |
262 i -= 17; | |
263 n <<= i; | |
264 return n; | |
265 } | |
266 | |
267 // The array will be filled this way: | |
268 // index size | |
269 // 0 [0, 1024) | |
270 // 1 [1024, 2048) | |
271 // 2 [2048, 4096) | |
272 // 3 [4K, 6K) | |
273 // ... | |
274 // 10 [18K, 20K) | |
275 // 11 [20K, 24K) | |
276 // 12 [24k, 28K) | |
277 // ... | |
278 // 15 [36k, 40K) | |
279 // 16 [40k, 64K) | |
280 // 17 [64K, 128K) | |
281 // 18 [128K, 256K) | |
282 // ... | |
283 // 23 [4M, 8M) | |
284 // 24 [8M, 16M) | |
285 // 25 [16M, 32M) | |
286 // 26 [32M, 64M) | |
287 // 27 [64M, ...) | |
288 int Stats::GetStatsBucket(int32 size) { | |
289 if (size < 1024) | |
290 return 0; | |
291 | |
292 // 10 slots more, until 20K. | |
293 if (size < 20 * 1024) | |
294 return size / 2048 + 1; | |
295 | |
296 // 5 slots more, from 20K to 40K. | |
297 if (size < 40 * 1024) | |
298 return (size - 20 * 1024) / 4096 + 11; | |
299 | |
300 // From this point on, use a logarithmic scale. | |
301 int result = LogBase2(size) + 1; | |
302 | |
303 static_assert(kDataSizesLength > 16, "update the scale"); | |
304 if (result >= kDataSizesLength) | |
305 result = kDataSizesLength - 1; | |
306 | |
307 return result; | |
308 } | |
309 | |
310 int Stats::GetRatio(Counters hit, Counters miss) const { | |
311 int64 ratio = GetCounter(hit) * 100; | |
312 if (!ratio) | |
313 return 0; | |
314 | |
315 ratio /= (GetCounter(hit) + GetCounter(miss)); | |
316 return static_cast<int>(ratio); | |
317 } | |
318 | |
319 } // namespace disk_cache | |
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