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1 | ||
2 | /* | |
3 | * $Id$ | |
4 | * | |
5 | * DEBUG: section 70 Cache Digest | |
6 | * AUTHOR: Alex Rousskov | |
7 | * | |
8 | * SQUID Web Proxy Cache http://www.squid-cache.org/ | |
9 | * ---------------------------------------------------------- | |
10 | * | |
11 | * Squid is the result of efforts by numerous individuals from | |
12 | * the Internet community; see the CONTRIBUTORS file for full | |
13 | * details. Many organizations have provided support for Squid's | |
14 | * development; see the SPONSORS file for full details. Squid is | |
15 | * Copyrighted (C) 2001 by the Regents of the University of | |
16 | * California; see the COPYRIGHT file for full details. Squid | |
17 | * incorporates software developed and/or copyrighted by other | |
18 | * sources; see the CREDITS file for full details. | |
19 | * | |
20 | * This program is free software; you can redistribute it and/or modify | |
21 | * it under the terms of the GNU General Public License as published by | |
22 | * the Free Software Foundation; either version 2 of the License, or | |
23 | * (at your option) any later version. | |
24 | * | |
25 | * This program is distributed in the hope that it will be useful, | |
26 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
27 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
28 | * GNU General Public License for more details. | |
29 | * | |
30 | * You should have received a copy of the GNU General Public License | |
31 | * along with this program; if not, write to the Free Software | |
32 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. | |
33 | * | |
34 | */ | |
35 | ||
36 | #include "squid.h" | |
37 | #include "Store.h" | |
38 | ||
39 | #if USE_CACHE_DIGESTS | |
40 | ||
41 | /* local types */ | |
42 | ||
43 | typedef struct { | |
44 | int bit_count; /* total number of bits */ | |
45 | int bit_on_count; /* #bits turned on */ | |
46 | int bseq_len_sum; /* sum of all bit seq length */ | |
47 | int bseq_count; /* number of bit seqs */ | |
48 | } CacheDigestStats; | |
49 | ||
50 | /* local functions */ | |
51 | static void cacheDigestHashKey(const CacheDigest * cd, const cache_key * key); | |
52 | ||
53 | /* static array used by cacheDigestHashKey for optimization purposes */ | |
54 | static u_int32_t hashed_keys[4]; | |
55 | ||
56 | static void | |
57 | cacheDigestInit(CacheDigest * cd, int capacity, int bpe) | |
58 | { | |
59 | const size_t mask_size = cacheDigestCalcMaskSize(capacity, bpe); | |
60 | assert(cd); | |
61 | assert(capacity > 0 && bpe > 0); | |
62 | assert(mask_size > 0); | |
63 | cd->capacity = capacity; | |
64 | cd->bits_per_entry = bpe; | |
65 | cd->mask_size = mask_size; | |
66 | cd->mask = (char *)xcalloc(cd->mask_size, 1); | |
67 | debugs(70, 2, "cacheDigestInit: capacity: " << cd->capacity << " entries, bpe: " << cd->bits_per_entry << "; size: " | |
68 | << cd->mask_size << " bytes"); | |
69 | } | |
70 | ||
71 | CacheDigest * | |
72 | cacheDigestCreate(int capacity, int bpe) | |
73 | { | |
74 | CacheDigest *cd = (CacheDigest *)memAllocate(MEM_CACHE_DIGEST); | |
75 | assert(SQUID_MD5_DIGEST_LENGTH == 16); /* our hash functions rely on 16 byte keys */ | |
76 | cacheDigestInit(cd, capacity, bpe); | |
77 | return cd; | |
78 | } | |
79 | ||
80 | static void | |
81 | cacheDigestClean(CacheDigest * cd) | |
82 | { | |
83 | assert(cd); | |
84 | xfree(cd->mask); | |
85 | cd->mask = NULL; | |
86 | } | |
87 | ||
88 | void | |
89 | cacheDigestDestroy(CacheDigest * cd) | |
90 | { | |
91 | assert(cd); | |
92 | cacheDigestClean(cd); | |
93 | memFree(cd, MEM_CACHE_DIGEST); | |
94 | } | |
95 | ||
96 | CacheDigest * | |
97 | cacheDigestClone(const CacheDigest * cd) | |
98 | { | |
99 | CacheDigest *clone; | |
100 | assert(cd); | |
101 | clone = cacheDigestCreate(cd->capacity, cd->bits_per_entry); | |
102 | clone->count = cd->count; | |
103 | clone->del_count = cd->del_count; | |
104 | assert(cd->mask_size == clone->mask_size); | |
105 | xmemcpy(clone->mask, cd->mask, cd->mask_size); | |
106 | return clone; | |
107 | } | |
108 | ||
109 | void | |
110 | cacheDigestClear(CacheDigest * cd) | |
111 | { | |
112 | assert(cd); | |
113 | cd->count = cd->del_count = 0; | |
114 | memset(cd->mask, 0, cd->mask_size); | |
115 | } | |
116 | ||
117 | /* changes mask size, resets bits to 0, preserves "cd" pointer */ | |
118 | void | |
119 | cacheDigestChangeCap(CacheDigest * cd, int new_cap) | |
120 | { | |
121 | assert(cd); | |
122 | cacheDigestClean(cd); | |
123 | cacheDigestInit(cd, new_cap, cd->bits_per_entry); | |
124 | } | |
125 | ||
126 | /* returns true if the key belongs to the digest */ | |
127 | int | |
128 | cacheDigestTest(const CacheDigest * cd, const cache_key * key) | |
129 | { | |
130 | assert(cd && key); | |
131 | /* hash */ | |
132 | cacheDigestHashKey(cd, key); | |
133 | /* test corresponding bits */ | |
134 | return | |
135 | CBIT_TEST(cd->mask, hashed_keys[0]) && | |
136 | CBIT_TEST(cd->mask, hashed_keys[1]) && | |
137 | CBIT_TEST(cd->mask, hashed_keys[2]) && | |
138 | CBIT_TEST(cd->mask, hashed_keys[3]); | |
139 | } | |
140 | ||
141 | void | |
142 | cacheDigestAdd(CacheDigest * cd, const cache_key * key) | |
143 | { | |
144 | assert(cd && key); | |
145 | /* hash */ | |
146 | cacheDigestHashKey(cd, key); | |
147 | /* turn on corresponding bits */ | |
148 | #if CD_FAST_ADD | |
149 | ||
150 | CBIT_SET(cd->mask, hashed_keys[0]); | |
151 | CBIT_SET(cd->mask, hashed_keys[1]); | |
152 | CBIT_SET(cd->mask, hashed_keys[2]); | |
153 | CBIT_SET(cd->mask, hashed_keys[3]); | |
154 | #else | |
155 | ||
156 | { | |
157 | int on_xition_cnt = 0; | |
158 | ||
159 | if (!CBIT_TEST(cd->mask, hashed_keys[0])) { | |
160 | CBIT_SET(cd->mask, hashed_keys[0]); | |
161 | on_xition_cnt++; | |
162 | } | |
163 | ||
164 | if (!CBIT_TEST(cd->mask, hashed_keys[1])) { | |
165 | CBIT_SET(cd->mask, hashed_keys[1]); | |
166 | on_xition_cnt++; | |
167 | } | |
168 | ||
169 | if (!CBIT_TEST(cd->mask, hashed_keys[2])) { | |
170 | CBIT_SET(cd->mask, hashed_keys[2]); | |
171 | on_xition_cnt++; | |
172 | } | |
173 | ||
174 | if (!CBIT_TEST(cd->mask, hashed_keys[3])) { | |
175 | CBIT_SET(cd->mask, hashed_keys[3]); | |
176 | on_xition_cnt++; | |
177 | } | |
178 | ||
179 | statHistCount(&statCounter.cd.on_xition_count, on_xition_cnt); | |
180 | } | |
181 | #endif | |
182 | cd->count++; | |
183 | } | |
184 | ||
185 | void | |
186 | cacheDigestDel(CacheDigest * cd, const cache_key * key) | |
187 | { | |
188 | assert(cd && key); | |
189 | cd->del_count++; | |
190 | /* we do not support deletions from the digest */ | |
191 | } | |
192 | ||
193 | /* returns mask utilization parameters */ | |
194 | static void | |
195 | cacheDigestStats(const CacheDigest * cd, CacheDigestStats * stats) | |
196 | { | |
197 | int on_count = 0; | |
198 | int pos = cd->mask_size * 8; | |
199 | int seq_len_sum = 0; | |
200 | int seq_count = 0; | |
201 | int cur_seq_len = 0; | |
202 | int cur_seq_type = 1; | |
203 | assert(stats); | |
204 | memset(stats, 0, sizeof(*stats)); | |
205 | ||
206 | while (pos-- > 0) { | |
207 | const int is_on = 0 != CBIT_TEST(cd->mask, pos); | |
208 | ||
209 | if (is_on) | |
210 | on_count++; | |
211 | ||
212 | if (is_on != cur_seq_type || !pos) { | |
213 | seq_len_sum += cur_seq_len; | |
214 | seq_count++; | |
215 | cur_seq_type = is_on; | |
216 | cur_seq_len = 0; | |
217 | } | |
218 | ||
219 | cur_seq_len++; | |
220 | } | |
221 | ||
222 | stats->bit_count = cd->mask_size * 8; | |
223 | stats->bit_on_count = on_count; | |
224 | stats->bseq_len_sum = seq_len_sum; | |
225 | stats->bseq_count = seq_count; | |
226 | } | |
227 | ||
228 | int | |
229 | cacheDigestBitUtil(const CacheDigest * cd) | |
230 | { | |
231 | CacheDigestStats stats; | |
232 | assert(cd); | |
233 | cacheDigestStats(cd, &stats); | |
234 | return xpercentInt(stats.bit_on_count, stats.bit_count); | |
235 | } | |
236 | ||
237 | void | |
238 | cacheDigestGuessStatsUpdate(cd_guess_stats * stats, int real_hit, int guess_hit) | |
239 | { | |
240 | assert(stats); | |
241 | ||
242 | if (real_hit) { | |
243 | if (guess_hit) | |
244 | stats->true_hits++; | |
245 | else | |
246 | stats->false_misses++; | |
247 | } else { | |
248 | if (guess_hit) | |
249 | stats->false_hits++; | |
250 | else | |
251 | stats->true_misses++; | |
252 | } | |
253 | } | |
254 | ||
255 | void | |
256 | cacheDigestGuessStatsReport(const cd_guess_stats * stats, StoreEntry * sentry, const char *label) | |
257 | { | |
258 | const int true_count = stats->true_hits + stats->true_misses; | |
259 | const int false_count = stats->false_hits + stats->false_misses; | |
260 | const int hit_count = stats->true_hits + stats->false_hits; | |
261 | const int miss_count = stats->true_misses + stats->false_misses; | |
262 | const int tot_count = true_count + false_count; | |
263 | ||
264 | assert(label); | |
265 | assert(tot_count == hit_count + miss_count); /* paranoid */ | |
266 | ||
267 | if (!tot_count) { | |
268 | storeAppendPrintf(sentry, "no guess stats for %s available\n", label); | |
269 | return; | |
270 | } | |
271 | ||
272 | storeAppendPrintf(sentry, "Digest guesses stats for %s:\n", label); | |
273 | storeAppendPrintf(sentry, "guess\t hit\t\t miss\t\t total\t\t\n"); | |
274 | storeAppendPrintf(sentry, " \t #\t %%\t #\t %%\t #\t %%\t\n"); | |
275 | storeAppendPrintf(sentry, "true\t %d\t %.2f\t %d\t %.2f\t %d\t %.2f\n", | |
276 | stats->true_hits, xpercent(stats->true_hits, tot_count), | |
277 | stats->true_misses, xpercent(stats->true_misses, tot_count), | |
278 | true_count, xpercent(true_count, tot_count)); | |
279 | storeAppendPrintf(sentry, "false\t %d\t %.2f\t %d\t %.2f\t %d\t %.2f\n", | |
280 | stats->false_hits, xpercent(stats->false_hits, tot_count), | |
281 | stats->false_misses, xpercent(stats->false_misses, tot_count), | |
282 | false_count, xpercent(false_count, tot_count)); | |
283 | storeAppendPrintf(sentry, "all\t %d\t %.2f\t %d\t %.2f\t %d\t %.2f\n", | |
284 | hit_count, xpercent(hit_count, tot_count), | |
285 | miss_count, xpercent(miss_count, tot_count), | |
286 | tot_count, xpercent(tot_count, tot_count)); | |
287 | storeAppendPrintf(sentry, "\tclose_hits: %d ( %d%%) /* cd said hit, doc was in the peer cache, but we got a miss */\n", | |
288 | stats->close_hits, xpercentInt(stats->close_hits, stats->false_hits)); | |
289 | } | |
290 | ||
291 | void | |
292 | cacheDigestReport(CacheDigest * cd, const char *label, StoreEntry * e) | |
293 | { | |
294 | CacheDigestStats stats; | |
295 | assert(cd && e); | |
296 | cacheDigestStats(cd, &stats); | |
297 | storeAppendPrintf(e, "%s digest: size: %d bytes\n", | |
298 | label ? label : "", stats.bit_count / 8 | |
299 | ); | |
300 | storeAppendPrintf(e, "\t entries: count: %d capacity: %d util: %d%%\n", | |
301 | cd->count, | |
302 | cd->capacity, | |
303 | xpercentInt(cd->count, cd->capacity) | |
304 | ); | |
305 | storeAppendPrintf(e, "\t deletion attempts: %d\n", | |
306 | cd->del_count | |
307 | ); | |
308 | storeAppendPrintf(e, "\t bits: per entry: %d on: %d capacity: %d util: %d%%\n", | |
309 | cd->bits_per_entry, | |
310 | stats.bit_on_count, stats.bit_count, | |
311 | xpercentInt(stats.bit_on_count, stats.bit_count) | |
312 | ); | |
313 | storeAppendPrintf(e, "\t bit-seq: count: %d avg.len: %.2f\n", | |
314 | stats.bseq_count, | |
315 | xdiv(stats.bseq_len_sum, stats.bseq_count) | |
316 | ); | |
317 | } | |
318 | ||
319 | size_t | |
320 | cacheDigestCalcMaskSize(int cap, int bpe) | |
321 | { | |
322 | return (size_t) (cap * bpe + 7) / 8; | |
323 | } | |
324 | ||
325 | static void | |
326 | cacheDigestHashKey(const CacheDigest * cd, const cache_key * key) | |
327 | { | |
328 | const unsigned int bit_count = cd->mask_size * 8; | |
329 | unsigned int tmp_keys[4]; | |
330 | /* we must memcpy to ensure alignment */ | |
331 | xmemcpy(tmp_keys, key, sizeof(tmp_keys)); | |
332 | hashed_keys[0] = htonl(tmp_keys[0]) % bit_count; | |
333 | hashed_keys[1] = htonl(tmp_keys[1]) % bit_count; | |
334 | hashed_keys[2] = htonl(tmp_keys[2]) % bit_count; | |
335 | hashed_keys[3] = htonl(tmp_keys[3]) % bit_count; | |
336 | debugs(70, 9, "cacheDigestHashKey: " << storeKeyText(key) << " -(" << | |
337 | bit_count << ")-> " << hashed_keys[0] << " " << hashed_keys[1] << | |
338 | " " << hashed_keys[2] << " " << hashed_keys[3]); | |
339 | } | |
340 | ||
341 | #endif |