mdw@git.distorted.org.uk Git - mLib/blob - test/bench.h

   1 /* -*-c-*-
   2  *
   3  * Benchmarking support
   4  *
   5  * (c) 2023 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software: you can redistribute it and/or modify it under
  13  * the terms of the GNU Library General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or (at
  15  * your option) any later version.
  16  *
  17  * mLib is distributed in the hope that it will be useful, but WITHOUT
  18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
  20  * License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib.  If not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  25  * USA.
  26  */
  27
  28 #ifndef MLIB_BENCH_H
  29 #define MLIB_BENCH_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #ifndef MLIB_BITS_H
  38 #  include "bits.h"
  39 #endif
  40
  41 #ifndef MLIB_DSTR_H
  42 #  include "dstr.h"
  43 #endif
  44
  45 /*----- Data structures ---------------------------------------------------*/
  46
  47 struct bench_time {
  48   unsigned f;                           /* flags */
  49 #define BTF_TIMEOK 1u                   /*   @s@ ad @ns@ slots are value */
  50 #define BTF_CYOK 2u                     /*   @cy@ slot is valid */
  51 #define BTF_ANY (BTF_TIMEOK | BTF_CYOK) /*   some part is useful */
  52   kludge64 s; uint32 ns;                /* real time, seconds and nanos */
  53   kludge64 cy;                          /* count of CPU cycles */
  54 };
  55
  56 struct bench_timing {
  57   unsigned f;                           /* flags (@BTF_...@) */
  58   double n, t, cy;                      /* count, time, and cycles */
  59 };
  60
  61 struct bench_timer { const struct bench_timerops *ops; };
  62
  63 struct bench_timerops {
  64   void (*describe)(struct bench_timer */*bt*/, dstr */*d*/);
  65     /* Write a description of the timer to @d@. */
  66
  67   void (*now)(struct bench_timer */*bt*/, struct bench_time */*t_out*/);
  68     /* Fill in @*t_out@ with the current time. v*/
  69
  70   void (*destroy)(struct bench_timer */*bt*/);
  71     /* Release the timer and any resources it holds. */
  72 };
  73
  74 struct bench_state {
  75   struct bench_timer *tm;               /* a timer */
  76   double target_s;                      /* target time to run benchmarks */
  77   unsigned f;                           /* calibration flags (@BTF_...@) */
  78 #define BTF_CLB 0x0100                  /*   tried calibrating */
  79   struct { double m, c; } clk, cy;      /* calculated overheads */
  80 };
  81
  82 typedef void bench_fn(unsigned long /*n*/, void */*ctx*/);
  83   /* Run the benchmark @n@ times, given a context pointer @ctx@. */
  84
  85 /*----- Functions provided ------------------------------------------------*/
  86
  87 /* --- @bench_createtimer@ --- *
  88  *
  89  * Arguments:   @const char *config@ = user-supplied configuration string
  90  *
  91  * Returns:     A freshly constructed standard timer object, or null on
  92  *              failure.
  93  *
  94  * Use:         Allocate a timer.  Dispose of it by calling
  95  *              @tm->ops->destroy(tm)@ when you're done.
  96  *
  97  *              Applications should not set configuration strings except as
  98  *              established by user action, e.g., from a command-line option,
  99  *              environment variable, or configuration file.
 100  */
 101
 102 extern struct bench_timer *bench_createtimer(const char *config);
 103
 104 /* --- @bench_init@ --- *
 105  *
 106  * Arguments:   @struct bench_state *b@ = bench state to initialize
 107  *              @struct bench_timer *tm@ = timer to attach, or null
 108  *
 109  * Returns:     Zero on success, %$-1$% on failure.
 110  *
 111  * Use:         Initialize the benchmark state.  On success, the timer state
 112  *              still needs to be calibrated (use @bench_calibrate@) before
 113  *              it can be used, but this will be done automatically by
 114  *              @bench_measure@ if it's not done by hand earlier.  The timer
 115  *              is now owned by the benchmark state and will be destroyed by
 116  *              @bench_destroy@.
 117  *
 118  *              The only reason for failure is if @tm@ was null on entry,
 119  *              and automatic construction of a timer failed.  The state is
 120  *              safe to discard, but calling @bench_destroy@ is safe too.
 121  */
 122
 123 extern int bench_init(struct bench_state */*b*/, struct bench_timer */*tm*/);
 124
 125 /* --- @bench_destroy@ --- *
 126  *
 127  * Arguments:   @struct bench_state *b@ = bench state
 128  *
 129  * Returns:     ---
 130  *
 131  * Use:         Destroy the benchmark state, releasing the resources that it
 132  *              holds.
 133  */
 134
 135 extern void bench_destroy(struct bench_state */*b*/);
 136
 137 /* --- @bench_calibrate@ --- *
 138  *
 139  * Arguments:   @struct bench_state *b@ = bench state
 140  *
 141  * Returns:     Zero on success, %$-1$% if calibration failed.
 142  *
 143  * Use:         Calibrate the benchmark state, so that it can be used to
 144  *              measure performance reasonably accurately.
 145  */
 146
 147 extern int bench_calibrate(struct bench_state */*b*/);
 148
 149 /* --- @bench_measure@ --- *
 150  *
 151  * Arguments:   @struct bench_state *b@ = benchmark state
 152  *              @struct bench_timing *t_out@ = where to leave the timing
 153  *              @double base@ = number of internal units per call
 154  *              @bench_fn *fn@, @void *ctx@ = benchmark function to run
 155  *
 156  * Returns:     Zero on success, %$-1$% if timing failed.
 157  *
 158  * Use:         Measure a function.  The function @fn@ is called adaptively
 159  *              with an iteration count @n@ set so as to run for
 160  *              approximately @b->target_s@ seconds.
 161  *
 162  *              The result is left in @*t_out@, with @t_out->n@ counting the
 163  *              final product of the iteration count and @base@ (which might,
 164  *              e.g., reflect the number of inner iterations the function
 165  *              performs, or the number of bytes it processes per iteration).
 166  */
 167
 168 extern int bench_measure(struct bench_state */*b*/,
 169                          struct bench_timing */*t_out*/,
 170                          double /*base*/, bench_fn */*fn*/, void */*ctx*/);
 171
 172 /*----- That's all, folks -------------------------------------------------*/
 173
 174 #ifdef __cplusplus
 175   }
 176 #endif
 177
 178 #endif