1 /*****************************************************************************
2 * RRDtool 1.2.99907080300 Copyright by Tobi Oetiker, 1997-2007
3 *****************************************************************************
4 * rrd_hw.c : Support for Holt-Winters Smoothing/ Aberrant Behavior Detection
5 *****************************************************************************
6 * Initial version by Jake Brutlag, WebTV Networks, 5/1/00
7 *****************************************************************************/
9 #include "rrd_tool.h"
10 #include "rrd_hw.h"
11 #include "rrd_hw_math.h"
12 #include "rrd_hw_update.h"
14 #define hw_dep_idx(rrd, rra_idx) rrd->rra_def[rra_idx].par[RRA_dependent_rra_idx].u_cnt
16 /* #define DEBUG */
18 /* private functions */
19 static unsigned long MyMod(
20 signed long val,
21 unsigned long mod);
23 int lookup_seasonal(
24 rrd_t *rrd,
25 unsigned long rra_idx,
26 unsigned long rra_start,
27 rrd_file_t *rrd_file,
28 unsigned long offset,
29 rrd_value_t **seasonal_coef)
30 {
31 unsigned long pos_tmp;
33 /* rra_ptr[].cur_row points to the rra row to be written; this function
34 * reads cur_row + offset */
35 unsigned long row_idx = rrd->rra_ptr[rra_idx].cur_row + offset;
37 /* handle wrap around */
38 if (row_idx >= rrd->rra_def[rra_idx].row_cnt)
39 row_idx = row_idx % (rrd->rra_def[rra_idx].row_cnt);
41 /* rra_start points to the appropriate rra block in the file */
42 /* compute the pointer to the appropriate location in the file */
43 pos_tmp =
44 rra_start +
45 (row_idx) * (rrd->stat_head->ds_cnt) * sizeof(rrd_value_t);
47 /* allocate memory if need be */
48 if (*seasonal_coef == NULL)
49 *seasonal_coef =
50 (rrd_value_t *) malloc((rrd->stat_head->ds_cnt) *
51 sizeof(rrd_value_t));
52 if (*seasonal_coef == NULL) {
53 rrd_set_error("memory allocation failure: seasonal coef");
54 return -1;
55 }
57 if (!rrd_seek(rrd_file, pos_tmp, SEEK_SET)) {
58 if (rrd_read
59 (rrd_file, *seasonal_coef,
60 sizeof(rrd_value_t) * rrd->stat_head->ds_cnt)
61 == (ssize_t) (sizeof(rrd_value_t) * rrd->stat_head->ds_cnt)) {
62 /* success! */
63 /* we can safely ignore the rule requiring a seek operation between read
64 * and write, because this read moves the file pointer to somewhere
65 * in the file other than the next write location.
66 * */
67 return 0;
68 } else {
69 rrd_set_error("read operation failed in lookup_seasonal(): %lu\n",
70 pos_tmp);
71 }
72 } else {
73 rrd_set_error("seek operation failed in lookup_seasonal(): %lu\n",
74 pos_tmp);
75 }
77 return -1;
78 }
80 /* For the specified CDP prep area and the FAILURES RRA,
81 * erase all history of past violations.
82 */
83 void erase_violations(
84 rrd_t *rrd,
85 unsigned long cdp_idx,
86 unsigned long rra_idx)
87 {
88 unsigned short i;
89 char *violations_array;
91 /* check that rra_idx is a CF_FAILURES array */
92 if (cf_conv(rrd->rra_def[rra_idx].cf_nam) != CF_FAILURES) {
93 #ifdef DEBUG
94 fprintf(stderr, "erase_violations called for non-FAILURES RRA: %s\n",
95 rrd->rra_def[rra_idx].cf_nam);
96 #endif
97 return;
98 }
99 #ifdef DEBUG
100 fprintf(stderr, "scratch buffer before erase:\n");
101 for (i = 0; i < MAX_CDP_PAR_EN; i++) {
102 fprintf(stderr, "%lu ", rrd->cdp_prep[cdp_idx].scratch[i].u_cnt);
103 }
104 fprintf(stderr, "\n");
105 #endif
107 /* WARNING: an array of longs on disk is treated as an array of chars
108 * in memory. */
109 violations_array = (char *) ((void *) rrd->cdp_prep[cdp_idx].scratch);
110 /* erase everything in the part of the CDP scratch array that will be
111 * used to store violations for the current window */
112 for (i = rrd->rra_def[rra_idx].par[RRA_window_len].u_cnt; i > 0; i--) {
113 violations_array[i - 1] = 0;
114 }
115 #ifdef DEBUG
116 fprintf(stderr, "scratch buffer after erase:\n");
117 for (i = 0; i < MAX_CDP_PAR_EN; i++) {
118 fprintf(stderr, "%lu ", rrd->cdp_prep[cdp_idx].scratch[i].u_cnt);
119 }
120 fprintf(stderr, "\n");
121 #endif
122 }
124 /* Smooth a periodic array with a moving average: equal weights and
125 * length = 5% of the period. */
126 int apply_smoother(
127 rrd_t *rrd,
128 unsigned long rra_idx,
129 unsigned long rra_start,
130 rrd_file_t *rrd_file)
131 {
132 unsigned long i, j, k;
133 unsigned long totalbytes;
134 rrd_value_t *rrd_values;
135 unsigned long row_length = rrd->stat_head->ds_cnt;
136 unsigned long row_count = rrd->rra_def[rra_idx].row_cnt;
137 unsigned long offset;
138 FIFOqueue **buffers;
139 rrd_value_t *working_average;
140 rrd_value_t *baseline;
142 offset = floor(0.025 * row_count);
143 if (offset == 0)
144 return 0; /* no smoothing */
146 /* allocate memory */
147 totalbytes = sizeof(rrd_value_t) * row_length * row_count;
148 rrd_values = (rrd_value_t *) malloc(totalbytes);
149 if (rrd_values == NULL) {
150 rrd_set_error("apply smoother: memory allocation failure");
151 return -1;
152 }
154 /* rra_start is at the beginning of this rra */
155 if (rrd_seek(rrd_file, rra_start, SEEK_SET)) {
156 rrd_set_error("seek to rra %d failed", rra_start);
157 free(rrd_values);
158 return -1;
159 }
160 rrd_flush(rrd_file);
161 /* could read all data in a single block, but we need to
162 * check for NA values */
163 for (i = 0; i < row_count; ++i) {
164 for (j = 0; j < row_length; ++j) {
165 if (rrd_read
166 (rrd_file, &(rrd_values[i * row_length + j]),
167 sizeof(rrd_value_t) * 1)
168 != (ssize_t) (sizeof(rrd_value_t) * 1)) {
169 rrd_set_error("reading value failed: %s",
170 rrd_strerror(errno));
171 }
172 if (isnan(rrd_values[i * row_length + j])) {
173 /* can't apply smoothing, still uninitialized values */
174 #ifdef DEBUG
175 fprintf(stderr,
176 "apply_smoother: NA detected in seasonal array: %ld %ld\n",
177 i, j);
178 #endif
179 free(rrd_values);
180 return 0;
181 }
182 }
183 }
185 /* allocate queues, one for each data source */
186 buffers = (FIFOqueue **) malloc(sizeof(FIFOqueue *) * row_length);
187 for (i = 0; i < row_length; ++i) {
188 queue_alloc(&(buffers[i]), 2 * offset + 1);
189 }
190 /* need working average initialized to 0 */
191 working_average = (rrd_value_t *) calloc(row_length, sizeof(rrd_value_t));
192 baseline = (rrd_value_t *) calloc(row_length, sizeof(rrd_value_t));
194 /* compute sums of the first 2*offset terms */
195 for (i = 0; i < 2 * offset; ++i) {
196 k = MyMod(i - offset, row_count);
197 for (j = 0; j < row_length; ++j) {
198 queue_push(buffers[j], rrd_values[k * row_length + j]);
199 working_average[j] += rrd_values[k * row_length + j];
200 }
201 }
203 /* compute moving averages */
204 for (i = offset; i < row_count + offset; ++i) {
205 for (j = 0; j < row_length; ++j) {
206 k = MyMod(i, row_count);
207 /* add a term to the sum */
208 working_average[j] += rrd_values[k * row_length + j];
209 queue_push(buffers[j], rrd_values[k * row_length + j]);
211 /* reset k to be the center of the window */
212 k = MyMod(i - offset, row_count);
213 /* overwrite rdd_values entry, the old value is already
214 * saved in buffers */
215 rrd_values[k * row_length + j] =
216 working_average[j] / (2 * offset + 1);
217 baseline[j] += rrd_values[k * row_length + j];
219 /* remove a term from the sum */
220 working_average[j] -= queue_pop(buffers[j]);
221 }
222 }
224 for (i = 0; i < row_length; ++i) {
225 queue_dealloc(buffers[i]);
226 baseline[i] /= row_count;
227 }
228 free(buffers);
229 free(working_average);
231 if (cf_conv(rrd->rra_def[rra_idx].cf_nam) == CF_SEASONAL) {
232 rrd_value_t (
233 *init_seasonality) (
234 rrd_value_t seasonal_coef,
235 rrd_value_t intercept);
237 switch (cf_conv(rrd->rra_def[hw_dep_idx(rrd, rra_idx)].cf_nam)) {
238 case CF_HWPREDICT:
239 init_seasonality = hw_additive_init_seasonality;
240 break;
241 case CF_MHWPREDICT:
242 init_seasonality = hw_multiplicative_init_seasonality;
243 break;
244 default:
245 rrd_set_error("apply smoother: SEASONAL rra doesn't have "
246 "valid dependency: %s",
247 rrd->rra_def[hw_dep_idx(rrd, rra_idx)].cf_nam);
248 return -1;
249 }
251 for (j = 0; j < row_length; ++j) {
252 for (i = 0; i < row_count; ++i) {
253 rrd_values[i * row_length + j] =
254 init_seasonality(rrd_values[i * row_length + j],
255 baseline[j]);
256 }
257 /* update the baseline coefficient,
258 * first, compute the cdp_index. */
259 offset = hw_dep_idx(rrd, rra_idx) * row_length + j;
260 (rrd->cdp_prep[offset]).scratch[CDP_hw_intercept].u_val +=
261 baseline[j];
262 }
263 /* flush cdp to disk */
264 rrd_flush(rrd_file);
265 if (rrd_seek(rrd_file, sizeof(stat_head_t) +
266 rrd->stat_head->ds_cnt * sizeof(ds_def_t) +
267 rrd->stat_head->rra_cnt * sizeof(rra_def_t) +
268 sizeof(live_head_t) +
269 rrd->stat_head->ds_cnt * sizeof(pdp_prep_t), SEEK_SET)) {
270 rrd_set_error("apply_smoother: seek to cdp_prep failed");
271 free(rrd_values);
272 return -1;
273 }
274 if (rrd_write(rrd_file, rrd->cdp_prep,
275 sizeof(cdp_prep_t) *
276 (rrd->stat_head->rra_cnt) * rrd->stat_head->ds_cnt)
277 != (ssize_t) (sizeof(cdp_prep_t) * (rrd->stat_head->rra_cnt) *
278 (rrd->stat_head->ds_cnt))) {
279 rrd_set_error("apply_smoother: cdp_prep write failed");
280 free(rrd_values);
281 return -1;
282 }
283 }
285 /* endif CF_SEASONAL */
286 /* flush updated values to disk */
287 rrd_flush(rrd_file);
288 if (rrd_seek(rrd_file, rra_start, SEEK_SET)) {
289 rrd_set_error("apply_smoother: seek to pos %d failed", rra_start);
290 free(rrd_values);
291 return -1;
292 }
293 /* write as a single block */
294 if (rrd_write
295 (rrd_file, rrd_values, sizeof(rrd_value_t) * row_length * row_count)
296 != (ssize_t) (sizeof(rrd_value_t) * row_length * row_count)) {
297 rrd_set_error("apply_smoother: write failed to %lu", rra_start);
298 free(rrd_values);
299 return -1;
300 }
302 rrd_flush(rrd_file);
303 free(rrd_values);
304 free(baseline);
305 return 0;
306 }
308 /* Reset aberrant behavior model coefficients, including intercept, slope,
309 * seasonal, and seasonal deviation for the specified data source. */
310 void reset_aberrant_coefficients(
311 rrd_t *rrd,
312 rrd_file_t *rrd_file,
313 unsigned long ds_idx)
314 {
315 unsigned long cdp_idx, rra_idx, i;
316 unsigned long cdp_start, rra_start;
317 rrd_value_t nan_buffer = DNAN;
319 /* compute the offset for the cdp area */
320 cdp_start = sizeof(stat_head_t) +
321 rrd->stat_head->ds_cnt * sizeof(ds_def_t) +
322 rrd->stat_head->rra_cnt * sizeof(rra_def_t) +
323 sizeof(live_head_t) + rrd->stat_head->ds_cnt * sizeof(pdp_prep_t);
324 /* compute the offset for the first rra */
325 rra_start = cdp_start +
326 (rrd->stat_head->ds_cnt) * (rrd->stat_head->rra_cnt) *
327 sizeof(cdp_prep_t) + rrd->stat_head->rra_cnt * sizeof(rra_ptr_t);
329 /* loop over the RRAs */
330 for (rra_idx = 0; rra_idx < rrd->stat_head->rra_cnt; rra_idx++) {
331 cdp_idx = rra_idx * (rrd->stat_head->ds_cnt) + ds_idx;
332 switch (cf_conv(rrd->rra_def[rra_idx].cf_nam)) {
333 case CF_HWPREDICT:
334 case CF_MHWPREDICT:
335 init_hwpredict_cdp(&(rrd->cdp_prep[cdp_idx]));
336 break;
337 case CF_SEASONAL:
338 case CF_DEVSEASONAL:
339 /* don't use init_seasonal because it will reset burn-in, which
340 * means different data sources will be calling for the smoother
341 * at different times. */
342 rrd->cdp_prep[cdp_idx].scratch[CDP_hw_seasonal].u_val = DNAN;
343 rrd->cdp_prep[cdp_idx].scratch[CDP_hw_last_seasonal].u_val = DNAN;
344 /* move to first entry of data source for this rra */
345 rrd_seek(rrd_file, rra_start + ds_idx * sizeof(rrd_value_t),
346 SEEK_SET);
347 /* entries for the same data source are not contiguous,
348 * temporal entries are contiguous */
349 for (i = 0; i < rrd->rra_def[rra_idx].row_cnt; ++i) {
350 if (rrd_write(rrd_file, &nan_buffer, sizeof(rrd_value_t) * 1)
351 != sizeof(rrd_value_t) * 1) {
352 rrd_set_error
353 ("reset_aberrant_coefficients: write failed data source %lu rra %s",
354 ds_idx, rrd->rra_def[rra_idx].cf_nam);
355 return;
356 }
357 rrd_seek(rrd_file, (rrd->stat_head->ds_cnt - 1) *
358 sizeof(rrd_value_t), SEEK_CUR);
359 }
360 break;
361 case CF_FAILURES:
362 erase_violations(rrd, cdp_idx, rra_idx);
363 break;
364 default:
365 break;
366 }
367 /* move offset to the next rra */
368 rra_start += rrd->rra_def[rra_idx].row_cnt * rrd->stat_head->ds_cnt *
369 sizeof(rrd_value_t);
370 }
371 rrd_seek(rrd_file, cdp_start, SEEK_SET);
372 if (rrd_write(rrd_file, rrd->cdp_prep,
373 sizeof(cdp_prep_t) *
374 (rrd->stat_head->rra_cnt) * rrd->stat_head->ds_cnt)
375 != (ssize_t) (sizeof(cdp_prep_t) * (rrd->stat_head->rra_cnt) *
376 (rrd->stat_head->ds_cnt))) {
377 rrd_set_error("reset_aberrant_coefficients: cdp_prep write failed");
378 }
379 }
381 void init_hwpredict_cdp(
382 cdp_prep_t *cdp)
383 {
384 cdp->scratch[CDP_hw_intercept].u_val = DNAN;
385 cdp->scratch[CDP_hw_last_intercept].u_val = DNAN;
386 cdp->scratch[CDP_hw_slope].u_val = DNAN;
387 cdp->scratch[CDP_hw_last_slope].u_val = DNAN;
388 cdp->scratch[CDP_null_count].u_cnt = 1;
389 cdp->scratch[CDP_last_null_count].u_cnt = 1;
390 }
392 void init_seasonal_cdp(
393 cdp_prep_t *cdp)
394 {
395 cdp->scratch[CDP_hw_seasonal].u_val = DNAN;
396 cdp->scratch[CDP_hw_last_seasonal].u_val = DNAN;
397 cdp->scratch[CDP_init_seasonal].u_cnt = 1;
398 }
400 int update_aberrant_CF(
401 rrd_t *rrd,
402 rrd_value_t pdp_val,
403 enum cf_en current_cf,
404 unsigned long cdp_idx,
405 unsigned long rra_idx,
406 unsigned long ds_idx,
407 unsigned short CDP_scratch_idx,
408 rrd_value_t *seasonal_coef)
409 {
410 static hw_functions_t hw_multiplicative_functions = {
411 hw_multiplicative_calculate_prediction,
412 hw_multiplicative_calculate_intercept,
413 hw_calculate_slope,
414 hw_multiplicative_calculate_seasonality,
415 hw_multiplicative_init_seasonality,
416 hw_calculate_seasonal_deviation,
417 hw_init_seasonal_deviation,
418 1.0 // identity value
419 };
421 static hw_functions_t hw_additive_functions = {
422 hw_additive_calculate_prediction,
423 hw_additive_calculate_intercept,
424 hw_calculate_slope,
425 hw_additive_calculate_seasonality,
426 hw_additive_init_seasonality,
427 hw_calculate_seasonal_deviation,
428 hw_init_seasonal_deviation,
429 0.0 // identity value
430 };
432 rrd->cdp_prep[cdp_idx].scratch[CDP_scratch_idx].u_val = pdp_val;
433 switch (current_cf) {
434 case CF_HWPREDICT:
435 return update_hwpredict(rrd, cdp_idx, rra_idx, ds_idx,
436 CDP_scratch_idx, &hw_additive_functions);
437 case CF_MHWPREDICT:
438 return update_hwpredict(rrd, cdp_idx, rra_idx, ds_idx,
439 CDP_scratch_idx,
440 &hw_multiplicative_functions);
441 case CF_DEVPREDICT:
442 return update_devpredict(rrd, cdp_idx, rra_idx, ds_idx,
443 CDP_scratch_idx);
444 case CF_SEASONAL:
445 switch (cf_conv(rrd->rra_def[hw_dep_idx(rrd, rra_idx)].cf_nam)) {
446 case CF_HWPREDICT:
447 return update_seasonal(rrd, cdp_idx, rra_idx, ds_idx,
448 CDP_scratch_idx, seasonal_coef,
449 &hw_additive_functions);
450 case CF_MHWPREDICT:
451 return update_seasonal(rrd, cdp_idx, rra_idx, ds_idx,
452 CDP_scratch_idx, seasonal_coef,
453 &hw_multiplicative_functions);
454 default:
455 return -1;
456 }
457 case CF_DEVSEASONAL:
458 switch (cf_conv(rrd->rra_def[hw_dep_idx(rrd, rra_idx)].cf_nam)) {
459 case CF_HWPREDICT:
460 return update_devseasonal(rrd, cdp_idx, rra_idx, ds_idx,
461 CDP_scratch_idx, seasonal_coef,
462 &hw_additive_functions);
463 case CF_MHWPREDICT:
464 return update_devseasonal(rrd, cdp_idx, rra_idx, ds_idx,
465 CDP_scratch_idx, seasonal_coef,
466 &hw_multiplicative_functions);
467 default:
468 return -1;
469 }
470 case CF_FAILURES:
471 switch (cf_conv
472 (rrd->rra_def[hw_dep_idx(rrd, hw_dep_idx(rrd, rra_idx))].
473 cf_nam)) {
474 case CF_HWPREDICT:
475 return update_failures(rrd, cdp_idx, rra_idx, ds_idx,
476 CDP_scratch_idx, &hw_additive_functions);
477 case CF_MHWPREDICT:
478 return update_failures(rrd, cdp_idx, rra_idx, ds_idx,
479 CDP_scratch_idx,
480 &hw_multiplicative_functions);
481 default:
482 return -1;
483 }
484 case CF_AVERAGE:
485 default:
486 return 0;
487 }
488 return -1;
489 }
491 static unsigned long MyMod(
492 signed long val,
493 unsigned long mod)
494 {
495 unsigned long new_val;
497 if (val < 0)
498 new_val = ((unsigned long) abs(val)) % mod;
499 else
500 new_val = (val % mod);
502 if (val < 0)
503 return (mod - new_val);
504 else
505 return (new_val);
506 }
508 /* a standard fixed-capacity FIF0 queue implementation
509 * No overflow checking is performed. */
510 int queue_alloc(
511 FIFOqueue **q,
512 int capacity)
513 {
514 *q = (FIFOqueue *) malloc(sizeof(FIFOqueue));
515 if (*q == NULL)
516 return -1;
517 (*q)->queue = (rrd_value_t *) malloc(sizeof(rrd_value_t) * capacity);
518 if ((*q)->queue == NULL) {
519 free(*q);
520 return -1;
521 }
522 (*q)->capacity = capacity;
523 (*q)->head = capacity;
524 (*q)->tail = 0;
525 return 0;
526 }
528 int queue_isempty(
529 FIFOqueue *q)
530 {
531 return (q->head % q->capacity == q->tail);
532 }
534 void queue_push(
535 FIFOqueue *q,
536 rrd_value_t value)
537 {
538 q->queue[(q->tail)++] = value;
539 q->tail = q->tail % q->capacity;
540 }
542 rrd_value_t queue_pop(
543 FIFOqueue *q)
544 {
545 q->head = q->head % q->capacity;
546 return q->queue[(q->head)++];
547 }
549 void queue_dealloc(
550 FIFOqueue *q)
551 {
552 free(q->queue);
553 free(q);
554 }