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 #include <time.h>
  38
  39 #ifndef MLIB_BITS_H
  40 #  include "bits.h"
  41 #endif
  42
  43 #ifndef MLIB_DSTR_H
  44 #  include "dstr.h"
  45 #endif
  46
  47 /*----- Data structures ---------------------------------------------------*/
  48
  49 struct bench_time {
  50   unsigned f;                           /* flags */
  51 #define BTF_TIMEOK 1u                   /*   @s@ ad @ns@ slots are value */
  52 #define BTF_CYOK 2u                     /*   @cy@ slot is valid */
  53 #define BTF_ANY (BTF_TIMEOK | BTF_CYOK) /*   some part is useful */
  54   union {
  55     struct { kludge64 s; uint32 ns; } ts; /* @struct timespec@-ish */
  56     clock_t clk;                        /* @clock@ */
  57     kludge64 rawns;                     /* raw nanosecond count */
  58   } t;                                  /* time */
  59   kludge64 cy;                          /* count of CPU cycles */
  60 };
  61
  62 struct bench_timing {
  63   unsigned f;                           /* flags (@BTF_...@) */
  64   double n, t, cy;                      /* count, time, and cycles */
  65 };
  66
  67 struct bench_timer { const struct bench_timerops *ops; };
  68
  69 struct bench_timerops {
  70   void (*describe)(struct bench_timer */*bt*/, dstr */*d*/);
  71     /* Write a description of the timer to @d@. */
  72
  73   int (*now)(struct bench_timer */*bt*/, struct bench_time */*t_out*/,
  74               unsigned /*f*/);
  75 #define BTF_T0 0u                       /* fetching first time of a pair */
  76 #define BTF_T1 1u                       /* fetching second time of a pair */
  77     /* Fill in @*t_out@ with the current time.  Return zero on success
  78      * %%\emph{or} permanent failure; return %$-1$% on temporary failure.
  79      */
  80
  81   void (*diff)(struct bench_timer */*bt*/,
  82                struct bench_timing */*delta_out*/,
  83                const struct bench_time */*t0*/,
  84                const struct bench_time */*t1*/);
  85     /* Subtract the time @t0@ from the time @t1@, leaving the result in
  86      * @*delta_out@, setting flags as appropriate.
  87      */
  88
  89   void (*destroy)(struct bench_timer */*bt*/);
  90     /* Release the timer and any resources it holds. */
  91 };
  92
  93 struct bench_state {
  94   struct bench_timer *tm;               /* a timer */
  95   double target_s;                      /* target time to run benchmarks */
  96   unsigned f;                           /* calibration flags (@BTF_...@) */
  97 #define BTF_CLB 0x0100                  /*   tried calibrating */
  98   struct { double m, c; } clk, cy;      /* calculated overheads */
  99 };
 100
 101 typedef void bench_fn(unsigned long /*n*/, void */*ctx*/);
 102   /* Run the benchmark @n@ times, given a context pointer @ctx@. */
 103
 104 /*----- Functions provided ------------------------------------------------*/
 105
 106 /* --- @bench_createtimer@ --- *
 107  *
 108  * Arguments:   @const char *config@ = user-supplied configuration string
 109  *
 110  * Returns:     A freshly constructed standard timer object, or null on
 111  *              failure.
 112  *
 113  * Use:         Allocate a timer.  Dispose of it by calling
 114  *              @tm->ops->destroy(tm)@ when you're done.
 115  *
 116  *              Applications should not set configuration strings except as
 117  *              established by user action, e.g., from a command-line option,
 118  *              environment variable, or configuration file.
 119  */
 120
 121 extern struct bench_timer *bench_createtimer(const char *config);
 122
 123 /* --- @bench_init@ --- *
 124  *
 125  * Arguments:   @struct bench_state *b@ = bench state to initialize
 126  *              @struct bench_timer *tm@ = timer to attach, or null
 127  *
 128  * Returns:     Zero on success, %$-1$% on failure.
 129  *
 130  * Use:         Initialize the benchmark state.  On success, the timer state
 131  *              still needs to be calibrated (use @bench_calibrate@) before
 132  *              it can be used, but this will be done automatically by
 133  *              @bench_measure@ if it's not done by hand earlier.  The timer
 134  *              is now owned by the benchmark state and will be destroyed by
 135  *              @bench_destroy@.
 136  *
 137  *              The only reason for failure is if @tm@ was null on entry,
 138  *              and automatic construction of a timer failed.  The state is
 139  *              safe to discard, but calling @bench_destroy@ is safe too.
 140  */
 141
 142 extern int bench_init(struct bench_state */*b*/, struct bench_timer */*tm*/);
 143
 144 /* --- @bench_destroy@ --- *
 145  *
 146  * Arguments:   @struct bench_state *b@ = bench state
 147  *
 148  * Returns:     ---
 149  *
 150  * Use:         Destroy the benchmark state, releasing the resources that it
 151  *              holds.
 152  */
 153
 154 extern void bench_destroy(struct bench_state */*b*/);
 155
 156 /* --- @bench_calibrate@ --- *
 157  *
 158  * Arguments:   @struct bench_state *b@ = bench state
 159  *
 160  * Returns:     Zero on success, %$-1$% if calibration failed.
 161  *
 162  * Use:         Calibrate the benchmark state, so that it can be used to
 163  *              measure performance reasonably accurately.
 164  */
 165
 166 extern int bench_calibrate(struct bench_state */*b*/);
 167
 168 /* --- @bench_measure@ --- *
 169  *
 170  * Arguments:   @struct bench_state *b@ = benchmark state
 171  *              @struct bench_timing *t_out@ = where to leave the timing
 172  *              @double base@ = number of internal units per call
 173  *              @bench_fn *fn@, @void *ctx@ = benchmark function to run
 174  *
 175  * Returns:     Zero on success, %$-1$% if timing failed.
 176  *
 177  * Use:         Measure a function.  The function @fn@ is called adaptively
 178  *              with an iteration count @n@ set so as to run for
 179  *              approximately @b->target_s@ seconds.
 180  *
 181  *              The result is left in @*t_out@, with @t_out->n@ counting the
 182  *              final product of the iteration count and @base@ (which might,
 183  *              e.g., reflect the number of inner iterations the function
 184  *              performs, or the number of bytes it processes per iteration).
 185  */
 186
 187 extern int bench_measure(struct bench_state */*b*/,
 188                          struct bench_timing */*t_out*/,
 189                          double /*base*/, bench_fn */*fn*/, void */*ctx*/);
 190
 191 /*----- That's all, folks -------------------------------------------------*/
 192
 193 #ifdef __cplusplus
 194   }
 195 #endif
 196
 197 #endif