programs/timefn.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 * You may select, at your option, one of the above-listed licenses.
 */

#ifndef TIME_FN_H_MODULE_287987
#define TIME_FN_H_MODULE_287987

#if defined (__cplusplus)
extern "C" {
#endif



/*-****************************************
*  Types
******************************************/

#if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
# if defined(_AIX)
#  include <inttypes.h>
# else
#  include <stdint.h> /* uint64_t */
# endif
  typedef uint64_t           PTime;  /* Precise Time */
#else
  typedef unsigned long long PTime;  /* does not support compilers without long long support */
#endif

/* UTIL_time_t contains a nanosecond time counter.
 * The absolute value is not meaningful.
 * It's only valid to compute the difference between 2 measurements. */
typedef struct { PTime t; } UTIL_time_t;
#define UTIL_TIME_INITIALIZER { 0 }


/*-****************************************
*  Time functions
******************************************/

UTIL_time_t UTIL_getTime(void);

/* Timer resolution can be low on some platforms.
 * To improve accuracy, it's recommended to wait for a new tick
 * before starting benchmark measurements */
void UTIL_waitForNextTick(void);
/* tells if timefn will return correct time measurements
 * in presence of multi-threaded workload.
 * note : this is not the case if only C90 clock_t measurements are available */
int UTIL_support_MT_measurements(void);

PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd);
PTime UTIL_clockSpanNano(UTIL_time_t clockStart);

PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd);
PTime UTIL_clockSpanMicro(UTIL_time_t clockStart);

#define SEC_TO_MICRO ((PTime)1000000)  /* nb of microseconds in a second */


#if defined (__cplusplus)
}
#endif

#endif /* TIME_FN_H_MODULE_287987 */