uspace/lib/c/include/perf.h

   1 /*
   2  * Copyright (c) 2018 Vojtech Horky
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup libc
  30  * @{
  31  */
  32 /** @file
  33  * System performance measurement utilities.
  34  */
  35
  36 #ifndef _LIBC_PERF_H_
  37 #define _LIBC_PERF_H_
  38
  39 #include <time.h>
  40
  41 /** Stopwatch is THE way to measure elapsed time on HelenOS. */
  42 typedef struct {
  43         struct timespec start;
  44         struct timespec end;
  45 } stopwatch_t;
  46
  47 #define STOPWATCH_INITIALIZE_STATIC { { 0, 0 }, { 0, 0 } }
  48
  49 /** Initialize system stopwatch.
  50  *
  51  * @param stopwatch Stopwatch to initialize.
  52  */
  53 static inline void stopwatch_init(stopwatch_t *stopwatch)
  54 {
  55         stopwatch->start.tv_sec = 0;
  56         stopwatch->start.tv_nsec = 0;
  57         stopwatch->end.tv_sec = 0;
  58         stopwatch->end.tv_nsec = 0;
  59 }
  60
  61 /** Emulate elapsed time for use in tests.
  62  *
  63  * @param stopwatch Stopwatch to use.
  64  * @param nanos Elapsed time in nanoseconds to set.
  65  */
  66 static inline void stopwatch_set_nanos(stopwatch_t *stopwatch, nsec_t nanos)
  67 {
  68         stopwatch->start.tv_sec = 0;
  69         stopwatch->start.tv_nsec = 0;
  70         stopwatch->end.tv_sec = NSEC2SEC(nanos);
  71         stopwatch->end.tv_nsec = nanos - SEC2NSEC(stopwatch->end.tv_sec);
  72 }
  73
  74 /** Start the stopwatch.
  75  *
  76  * Note that repeated starts/stops do NOT aggregate the elapsed time.
  77  *
  78  * @param stopwatch Stopwatch to start.
  79  */
  80 static inline void stopwatch_start(stopwatch_t *stopwatch)
  81 {
  82         getuptime(&stopwatch->start);
  83 }
  84
  85 /** Stop the stopwatch.
  86  *
  87  * Note that repeated starts/stops do NOT aggregate the elapsed time.
  88  *
  89  * @param stopwatch Stopwatch to stop.
  90  */
  91 static inline void stopwatch_stop(stopwatch_t *stopwatch)
  92 {
  93         getuptime(&stopwatch->end);
  94 }
  95
  96 /** Get elapsed time in nanoseconds.
  97  *
  98  * @param stopwatch Stopwatch to read from.
  99  * @return Elapsed time in nanoseconds.
 100  */
 101 static inline nsec_t stopwatch_get_nanos(stopwatch_t *stopwatch)
 102 {
 103         return ts_sub_diff(&stopwatch->end, &stopwatch->start);
 104 }
 105
 106 #endif
 107
 108 /** @}
 109  */