timehist.c revision 356345 
1/*
2 * util/timehist.c - make histogram of time values.
3 *
4 * Copyright (c) 2007, NLnet Labs. All rights reserved.
5 *
6 * This software is open source.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
14 *
15 * Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
18 *
19 * Neither the name of the NLNET LABS nor the names of its contributors may
20 * be used to endorse or promote products derived from this software without
21 * specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36/**
37 * \file
38 *
39 * This file contains functions to make a histogram of time values.
40 */
41#include "config.h"
42#ifdef HAVE_TIME_H
43#include <time.h>
44#endif
45#include <sys/time.h>
46#include <sys/types.h>
47#include "util/timehist.h"
48#include "util/log.h"
49
50/** special timestwo operation for time values in histogram setup */
51static void
52timestwo(struct timeval* v)
53{
54#ifndef S_SPLINT_S
55	if(v->tv_sec == 0 && v->tv_usec == 0) {
56		v->tv_usec = 1;
57		return;
58	}
59	v->tv_sec *= 2;
60	v->tv_usec *= 2;
61	if(v->tv_usec == 1024*1024) {
62		/* nice values and easy to compute */
63		v->tv_sec = 1;
64		v->tv_usec = 0;
65	}
66#endif
67}
68
69/** do setup exponentially */
70static void
71dosetup(struct timehist* hist)
72{
73	struct timeval last;
74	size_t i;
75	memset(&last, 0, sizeof(last));
76	for(i=0; i<hist->num; i++) {
77		hist->buckets[i].lower = last;
78		timestwo(&last);
79		hist->buckets[i].upper = last;
80		hist->buckets[i].count = 0;
81	}
82}
83
84struct timehist* timehist_setup(void)
85{
86	struct timehist* hist = (struct timehist*)calloc(1,
87		sizeof(struct timehist));
88	if(!hist)
89		return NULL;
90	hist->num = NUM_BUCKETS_HIST;
91	hist->buckets = (struct th_buck*)calloc(hist->num,
92		sizeof(struct th_buck));
93	if(!hist->buckets) {
94		free(hist);
95		return NULL;
96	}
97	/* setup the buckets */
98	dosetup(hist);
99	return hist;
100}
101
102void timehist_delete(struct timehist* hist)
103{
104	if(!hist)
105		return;
106	free(hist->buckets);
107	free(hist);
108}
109
110void timehist_clear(struct timehist* hist)
111{
112	size_t i;
113	for(i=0; i<hist->num; i++)
114		hist->buckets[i].count = 0;
115}
116
117/** histogram compare of time values */
118static int
119timeval_smaller(const struct timeval* x, const struct timeval* y)
120{
121#ifndef S_SPLINT_S
122	if(x->tv_sec < y->tv_sec)
123		return 1;
124	else if(x->tv_sec == y->tv_sec) {
125		if(x->tv_usec <= y->tv_usec)
126			return 1;
127		else	return 0;
128	}
129	else	return 0;
130#endif
131}
132
133
134void timehist_insert(struct timehist* hist, struct timeval* tv)
135{
136	size_t i;
137	for(i=0; i<hist->num; i++) {
138		if(timeval_smaller(tv, &hist->buckets[i].upper)) {
139			hist->buckets[i].count++;
140			return;
141		}
142	}
143	/* dump in last bucket */
144	hist->buckets[hist->num-1].count++;
145}
146
147void timehist_print(struct timehist* hist)
148{
149#ifndef S_SPLINT_S
150	size_t i;
151	for(i=0; i<hist->num; i++) {
152		if(hist->buckets[i].count != 0) {
153			printf("%4d.%6.6d %4d.%6.6d %u\n",
154				(int)hist->buckets[i].lower.tv_sec,
155				(int)hist->buckets[i].lower.tv_usec,
156				(int)hist->buckets[i].upper.tv_sec,
157				(int)hist->buckets[i].upper.tv_usec,
158				(unsigned)hist->buckets[i].count);
159		}
160	}
161#endif
162}
163
164void timehist_log(struct timehist* hist, const char* name)
165{
166#ifndef S_SPLINT_S
167	size_t i;
168	log_info("[25%%]=%g median[50%%]=%g [75%%]=%g",
169		timehist_quartile(hist, 0.25),
170		timehist_quartile(hist, 0.50),
171		timehist_quartile(hist, 0.75));
172	/*        0000.000000 0000.000000 0 */
173	log_info("lower(secs) upper(secs) %s", name);
174	for(i=0; i<hist->num; i++) {
175		if(hist->buckets[i].count != 0) {
176			log_info("%4d.%6.6d %4d.%6.6d %u",
177				(int)hist->buckets[i].lower.tv_sec,
178				(int)hist->buckets[i].lower.tv_usec,
179				(int)hist->buckets[i].upper.tv_sec,
180				(int)hist->buckets[i].upper.tv_usec,
181				(unsigned)hist->buckets[i].count);
182		}
183	}
184#endif
185}
186
187/** total number in histogram */
188static size_t
189timehist_count(struct timehist* hist)
190{
191	size_t i, res = 0;
192	for(i=0; i<hist->num; i++)
193		res += hist->buckets[i].count;
194	return res;
195}
196
197double
198timehist_quartile(struct timehist* hist, double q)
199{
200	double lookfor, passed, res;
201	double low = 0, up = 0;
202	size_t i;
203	if(!hist || hist->num == 0)
204		return 0.;
205	/* look for i'th element, interpolated */
206	lookfor = (double)timehist_count(hist);
207	if(lookfor < 4)
208		return 0.; /* not enough elements for a good estimate */
209	lookfor *= q;
210	passed = 0;
211	i = 0;
212	while(i+1 < hist->num &&
213		passed+(double)hist->buckets[i].count < lookfor) {
214		passed += (double)hist->buckets[i++].count;
215	}
216	/* got the right bucket */
217#ifndef S_SPLINT_S
218	low = (double)hist->buckets[i].lower.tv_sec +
219		(double)hist->buckets[i].lower.tv_usec/1000000.;
220	up = (double)hist->buckets[i].upper.tv_sec +
221		(double)hist->buckets[i].upper.tv_usec/1000000.;
222#endif
223	res = (lookfor - passed)*(up-low)/((double)hist->buckets[i].count);
224	return low+res;
225}
226
227void
228timehist_export(struct timehist* hist, long long* array, size_t sz)
229{
230	size_t i;
231	if(!hist) return;
232	if(sz > hist->num)
233		sz = hist->num;
234	for(i=0; i<sz; i++)
235		array[i] = (long long)hist->buckets[i].count;
236}
237
238void
239timehist_import(struct timehist* hist, long long* array, size_t sz)
240{
241	size_t i;
242	if(!hist) return;
243	if(sz > hist->num)
244		sz = hist->num;
245	for(i=0; i<sz; i++)
246		hist->buckets[i].count = (size_t)array[i];
247}
248