include/qemu/timed-average.h

   1 /*
   2  * QEMU timed average computation
   3  *
   4  * Copyright (C) Nodalink, EURL. 2014
   5  * Copyright (C) Igalia, S.L. 2015
   6  *
   7  * Authors:
   8  *   Benoît Canet <benoit.canet@nodalink.com>
   9  *   Alberto Garcia <berto@igalia.com>
  10  *
  11  * This program is free software: you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation, either version 2 of the License, or
  14  * (at your option) version 3 or any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24
  25 #ifndef TIMED_AVERAGE_H
  26 #define TIMED_AVERAGE_H
  27
  28
  29 #include "qemu/timer.h"
  30
  31 typedef struct TimedAverageWindow TimedAverageWindow;
  32 typedef struct TimedAverage TimedAverage;
  33
  34 /* All fields of both structures are private */
  35
  36 struct TimedAverageWindow {
  37     uint64_t      min;             /* minimum value accounted in the window */
  38     uint64_t      max;             /* maximum value accounted in the window */
  39     uint64_t      sum;             /* sum of all values */
  40     uint64_t      count;           /* number of values */
  41     int64_t       expiration;      /* the end of the current window in ns */
  42 };
  43
  44 struct TimedAverage {
  45     uint64_t           period;     /* period in nanoseconds */
  46     TimedAverageWindow windows[2]; /* two overlapping windows of with
  47                                     * an offset of period / 2 between them */
  48     unsigned           current;    /* the current window index: it's also the
  49                                     * oldest window index */
  50     QEMUClockType      clock_type; /* the clock used */
  51 };
  52
  53 void timed_average_init(TimedAverage *ta, QEMUClockType clock_type,
  54                         uint64_t period);
  55
  56 void timed_average_account(TimedAverage *ta, uint64_t value);
  57
  58 uint64_t timed_average_min(TimedAverage *ta);
  59 uint64_t timed_average_avg(TimedAverage *ta);
  60 uint64_t timed_average_max(TimedAverage *ta);
  61 uint64_t timed_average_sum(TimedAverage *ta, uint64_t *elapsed);
  62
  63 #endif