stats.c

   1 /*
   2  * stats.c -- Statistics helpers
   3  *
   4  * Copyright (C) 2004 Henrique de Moraes Holschuh <hmh@debian.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #define _GNU_SOURCE
  22
  23 #ifndef HAVE_CONFIG_H
  24 #error Invalid or missing autoconf build environment
  25 #endif
  26
  27 #include "rng-tools-config.h"
  28
  29 #include <unistd.h>
  30 #include <stdint.h>
  31 #include <stdio.h>
  32 #include <sys/time.h>
  33 #include <time.h>
  34 #include <string.h>
  35
  36 #include "fips.h"
  37 #include "stats.h"
  38
  39
  40 static char stat_prefix[20] = "";
  41
  42 void set_stat_prefix(const char* prefix)
  43 {
  44         stat_prefix[sizeof(stat_prefix)-1] = 0;
  45         strncpy(stat_prefix, prefix, sizeof(stat_prefix)-1);
  46 }
  47
  48 static void scale_mult_unit(char *unit, int unitsize,
  49                        const char *baseunit,
  50                        double *value_min,
  51                        double *value_avg,
  52                        double *value_max)
  53 {
  54         int mult = 0;
  55         char multchar[] = "KMGTPE";
  56
  57         while ((*value_min >= 1024.0) && (*value_avg >= 1024.0) &&
  58                (*value_max >= 1024.0) && (mult < sizeof(multchar))) {
  59                 mult++;
  60                 *value_min = *value_min / 1024.0;
  61                 *value_max = *value_max / 1024.0;
  62                 *value_avg = *value_avg / 1024.0;
  63         }
  64         unit[unitsize-1] = 0;
  65         if (mult)
  66                 snprintf(unit, unitsize, "%ci%s", multchar[mult-1], baseunit);
  67         else
  68                 strncpy(unit, baseunit, unitsize);
  69 }
  70
  71 /* Computes elapsed time in microseconds */
  72 uint64_t elapsed_time(struct timeval *start,
  73                        struct timeval *stop)
  74 {
  75         uint64_t diff;
  76
  77         if (stop->tv_sec < start->tv_sec) return 0;
  78
  79         diff = (stop->tv_sec - start->tv_sec) * 1000000ULL;
  80         if (stop->tv_usec > start->tv_usec) {
  81                 diff += stop->tv_usec - start->tv_usec;
  82         } else {
  83                 diff -= start->tv_usec - stop->tv_usec;
  84         }
  85
  86         return diff;
  87 }
  88
  89 /* Updates min-max stat */
  90 void update_stat(struct rng_stat *stat, uint64_t value)
  91 {
  92         uint64_t overflow = stat->num_samples;
  93
  94         if ((stat->min == 0 ) || (value < stat->min)) stat->min = value;
  95         if (value > stat->max) stat->max = value;
  96         if (++stat->num_samples > overflow) {
  97                 stat->sum += value;
  98         } else {
  99                 stat->sum = value;
 100                 stat->num_samples = 1;
 101         }
 102 }
 103
 104 char *dump_stat_counter(char *buf, int size,
 105                        const char *msg, uint64_t value)
 106 {
 107         buf[size-1] = 0;
 108         snprintf(buf, size-1, "%s%s: %llu", stat_prefix, msg,
 109                  (unsigned long long) value);
 110
 111         return buf;
 112 }
 113
 114 char *dump_stat_stat(char *buf, int size,
 115                     const char *msg, const char *unit, struct rng_stat *stat)
 116 {
 117         double avg = 0.0;
 118
 119         if (stat->num_samples > 0)
 120                 avg = (double)stat->sum / stat->num_samples;
 121
 122         buf[size-1] = 0;
 123         snprintf(buf, size-1, "%s%s: (min=%llu; avg=%.3f; max=%llu)%s",
 124                  stat_prefix, msg, (unsigned long long) stat->min, avg,
 125                  (unsigned long long) stat->max, unit);
 126
 127         return buf;
 128 }
 129
 130 char *dump_stat_bw(char *buf, int size,
 131                   const char *msg, const char *unit,
 132                   struct rng_stat *stat,
 133                   uint64_t blocksize)
 134 {
 135         char unitscaled[20];
 136         double bw_avg = 0.0, bw_min = 0.0, bw_max = 0.0;
 137
 138         if (stat->max > 0)
 139                 bw_min = (1000000.0 * blocksize) / stat->max;
 140         if (stat->min > 0)
 141                 bw_max = (1000000.0 * blocksize) / stat->min;
 142         if (stat->num_samples > 0)
 143                 bw_avg = (1000000.0 * blocksize * stat->num_samples) / stat->sum;
 144
 145         scale_mult_unit(unitscaled, sizeof(unitscaled), unit,
 146                         &bw_min, &bw_avg, &bw_max);
 147
 148         buf[size-1] = 0;
 149         snprintf(buf, size-1, "%s%s: (min=%.3f; avg=%.3f; max=%.3f)%s/s",
 150                  stat_prefix, msg, bw_min, bw_avg, bw_max, unitscaled);
 151
 152         return buf;
 153 }
 154