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      1 /*
      2  * Copyright (c) Meta Platforms, Inc. and affiliates.
      3  * All rights reserved.
      4  *
      5  * This source code is licensed under both the BSD-style license (found in the
      6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
      7  * in the COPYING file in the root directory of this source tree).
      8  * You may select, at your option, one of the above-listed licenses.
      9  */
     10 
     11 #ifndef TIME_FN_H_MODULE_287987
     12 #define TIME_FN_H_MODULE_287987
     13 
     14 #if defined (__cplusplus)
     15 extern "C" {
     16 #endif
     17 
     18 
     19 
     20 /*-****************************************
     21 *  Types
     22 ******************************************/
     23 
     24 #if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
     25 # if defined(_AIX)
     26 #  include <inttypes.h>
     27 # else
     28 #  include <stdint.h> /* uint64_t */
     29 # endif
     30   typedef uint64_t           PTime;  /* Precise Time */
     31 #else
     32   typedef unsigned long long PTime;  /* does not support compilers without long long support */
     33 #endif
     34 
     35 /* UTIL_time_t contains a nanosecond time counter.
     36  * The absolute value is not meaningful.
     37  * It's only valid to compute the difference between 2 measurements. */
     38 typedef struct { PTime t; } UTIL_time_t;
     39 #define UTIL_TIME_INITIALIZER { 0 }
     40 
     41 
     42 /*-****************************************
     43 *  Time functions
     44 ******************************************/
     45 
     46 UTIL_time_t UTIL_getTime(void);
     47 
     48 /* Timer resolution can be low on some platforms.
     49  * To improve accuracy, it's recommended to wait for a new tick
     50  * before starting benchmark measurements */
     51 void UTIL_waitForNextTick(void);
     52 /* tells if timefn will return correct time measurements
     53  * in presence of multi-threaded workload.
     54  * note : this is not the case if only C90 clock_t measurements are available */
     55 int UTIL_support_MT_measurements(void);
     56 
     57 PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd);
     58 PTime UTIL_clockSpanNano(UTIL_time_t clockStart);
     59 
     60 PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd);
     61 PTime UTIL_clockSpanMicro(UTIL_time_t clockStart);
     62 
     63 #define SEC_TO_MICRO ((PTime)1000000)  /* nb of microseconds in a second */
     64 
     65 
     66 #if defined (__cplusplus)
     67 }
     68 #endif
     69 
     70 #endif /* TIME_FN_H_MODULE_287987 */
     71