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/*-------------------------------------------------------------------------
*
* instr_time.h
* portable high-precision interval timing
*
* This file provides an abstraction layer to hide portability issues in
* interval timing. On Unix we use clock_gettime() if available, else
* gettimeofday(). On Windows, gettimeofday() gives a low-precision result
* so we must use QueryPerformanceCounter() instead. These macros also give
* some breathing room to use other high-precision-timing APIs.
*
* The basic data type is instr_time, which all callers should treat as an
* opaque typedef. instr_time can store either an absolute time (of
* unspecified reference time) or an interval. The operations provided
* for it are:
*
* INSTR_TIME_IS_ZERO(t) is t equal to zero?
*
* INSTR_TIME_SET_ZERO(t) set t to zero (memset is acceptable too)
*
* INSTR_TIME_SET_CURRENT(t) set t to current time
*
* INSTR_TIME_ADD(x, y) x += y
*
* INSTR_TIME_SUBTRACT(x, y) x -= y
*
* INSTR_TIME_ACCUM_DIFF(x, y, z) x += (y - z)
*
* INSTR_TIME_GET_DOUBLE(t) convert t to double (in seconds)
*
* INSTR_TIME_GET_MILLISEC(t) convert t to double (in milliseconds)
*
* INSTR_TIME_GET_MICROSEC(t) convert t to uint64 (in microseconds)
*
* Note that INSTR_TIME_SUBTRACT and INSTR_TIME_ACCUM_DIFF convert
* absolute times to intervals. The INSTR_TIME_GET_xxx operations are
* only useful on intervals.
*
* When summing multiple measurements, it's recommended to leave the
* running sum in instr_time form (ie, use INSTR_TIME_ADD or
* INSTR_TIME_ACCUM_DIFF) and convert to a result format only at the end.
*
* Beware of multiple evaluations of the macro arguments.
*
*
* Copyright (c) 2001-2018, PostgreSQL Global Development Group
*
* src/include/portability/instr_time.h
*
*-------------------------------------------------------------------------
*/
#ifndef INSTR_TIME_H
#define INSTR_TIME_H
#ifndef WIN32
#ifdef HAVE_CLOCK_GETTIME
/* Use clock_gettime() */
#include <time.h>
/*
* The best clockid to use according to the POSIX spec is CLOCK_MONOTONIC,
* since that will give reliable interval timing even in the face of changes
* to the system clock. However, POSIX doesn't require implementations to
* provide anything except CLOCK_REALTIME, so fall back to that if we don't
* find CLOCK_MONOTONIC.
*
* Also, some implementations have nonstandard clockids with better properties
* than CLOCK_MONOTONIC. In particular, as of macOS 10.12, Apple provides
* CLOCK_MONOTONIC_RAW which is both faster to read and higher resolution than
* their version of CLOCK_MONOTONIC.
*/
#if defined(__darwin__) && defined(CLOCK_MONOTONIC_RAW)
#define PG_INSTR_CLOCK CLOCK_MONOTONIC_RAW
#elif defined(CLOCK_MONOTONIC)
#define PG_INSTR_CLOCK CLOCK_MONOTONIC
#else
#define PG_INSTR_CLOCK CLOCK_REALTIME
#endif
typedef struct timespec instr_time;
#define INSTR_TIME_IS_ZERO(t) ((t).tv_nsec == 0 && (t).tv_sec == 0)
#define INSTR_TIME_SET_ZERO(t) ((t).tv_sec = 0, (t).tv_nsec = 0)
#define INSTR_TIME_SET_CURRENT(t) ((void) clock_gettime(PG_INSTR_CLOCK, &(t)))
#define INSTR_TIME_ADD(x,y) \
do { \
(x).tv_sec += (y).tv_sec; \
(x).tv_nsec += (y).tv_nsec; \
/* Normalize */ \
while ((x).tv_nsec >= 1000000000) \
{ \
(x).tv_nsec -= 1000000000; \
(x).tv_sec++; \
} \
} while (0)
#define INSTR_TIME_SUBTRACT(x,y) \
do { \
(x).tv_sec -= (y).tv_sec; \
(x).tv_nsec -= (y).tv_nsec; \
/* Normalize */ \
while ((x).tv_nsec < 0) \
{ \
(x).tv_nsec += 1000000000; \
(x).tv_sec--; \
} \
} while (0)
#define INSTR_TIME_ACCUM_DIFF(x,y,z) \
do { \
(x).tv_sec += (y).tv_sec - (z).tv_sec; \
(x).tv_nsec += (y).tv_nsec - (z).tv_nsec; \
/* Normalize after each add to avoid overflow/underflow of tv_nsec */ \
while ((x).tv_nsec < 0) \
{ \
(x).tv_nsec += 1000000000; \
(x).tv_sec--; \
} \
while ((x).tv_nsec >= 1000000000) \
{ \
(x).tv_nsec -= 1000000000; \
(x).tv_sec++; \
} \
} while (0)
#define INSTR_TIME_GET_DOUBLE(t) \
(((double) (t).tv_sec) + ((double) (t).tv_nsec) / 1000000000.0)
#define INSTR_TIME_GET_MILLISEC(t) \
(((double) (t).tv_sec * 1000.0) + ((double) (t).tv_nsec) / 1000000.0)
#define INSTR_TIME_GET_MICROSEC(t) \
(((uint64) (t).tv_sec * (uint64) 1000000) + (uint64) ((t).tv_nsec / 1000))
#else /* !HAVE_CLOCK_GETTIME */
/* Use gettimeofday() */
#include <sys/time.h>
typedef struct timeval instr_time;
#define INSTR_TIME_IS_ZERO(t) ((t).tv_usec == 0 && (t).tv_sec == 0)
#define INSTR_TIME_SET_ZERO(t) ((t).tv_sec = 0, (t).tv_usec = 0)
#define INSTR_TIME_SET_CURRENT(t) gettimeofday(&(t), NULL)
#define INSTR_TIME_ADD(x,y) \
do { \
(x).tv_sec += (y).tv_sec; \
(x).tv_usec += (y).tv_usec; \
/* Normalize */ \
while ((x).tv_usec >= 1000000) \
{ \
(x).tv_usec -= 1000000; \
(x).tv_sec++; \
} \
} while (0)
#define INSTR_TIME_SUBTRACT(x,y) \
do { \
(x).tv_sec -= (y).tv_sec; \
(x).tv_usec -= (y).tv_usec; \
/* Normalize */ \
while ((x).tv_usec < 0) \
{ \
(x).tv_usec += 1000000; \
(x).tv_sec--; \
} \
} while (0)
#define INSTR_TIME_ACCUM_DIFF(x,y,z) \
do { \
(x).tv_sec += (y).tv_sec - (z).tv_sec; \
(x).tv_usec += (y).tv_usec - (z).tv_usec; \
/* Normalize after each add to avoid overflow/underflow of tv_usec */ \
while ((x).tv_usec < 0) \
{ \
(x).tv_usec += 1000000; \
(x).tv_sec--; \
} \
while ((x).tv_usec >= 1000000) \
{ \
(x).tv_usec -= 1000000; \
(x).tv_sec++; \
} \
} while (0)
#define INSTR_TIME_GET_DOUBLE(t) \
(((double) (t).tv_sec) + ((double) (t).tv_usec) / 1000000.0)
#define INSTR_TIME_GET_MILLISEC(t) \
(((double) (t).tv_sec * 1000.0) + ((double) (t).tv_usec) / 1000.0)
#define INSTR_TIME_GET_MICROSEC(t) \
(((uint64) (t).tv_sec * (uint64) 1000000) + (uint64) (t).tv_usec)
#endif /* HAVE_CLOCK_GETTIME */
#else /* WIN32 */
/* Use QueryPerformanceCounter() */
typedef LARGE_INTEGER instr_time;
#define INSTR_TIME_IS_ZERO(t) ((t).QuadPart == 0)
#define INSTR_TIME_SET_ZERO(t) ((t).QuadPart = 0)
#define INSTR_TIME_SET_CURRENT(t) QueryPerformanceCounter(&(t))
#define INSTR_TIME_ADD(x,y) \
((x).QuadPart += (y).QuadPart)
#define INSTR_TIME_SUBTRACT(x,y) \
((x).QuadPart -= (y).QuadPart)
#define INSTR_TIME_ACCUM_DIFF(x,y,z) \
((x).QuadPart += (y).QuadPart - (z).QuadPart)
#define INSTR_TIME_GET_DOUBLE(t) \
(((double) (t).QuadPart) / GetTimerFrequency())
#define INSTR_TIME_GET_MILLISEC(t) \
(((double) (t).QuadPart * 1000.0) / GetTimerFrequency())
#define INSTR_TIME_GET_MICROSEC(t) \
((uint64) (((double) (t).QuadPart * 1000000.0) / GetTimerFrequency()))
static inline double
GetTimerFrequency(void)
{
LARGE_INTEGER f;
QueryPerformanceFrequency(&f);
return (double) f.QuadPart;
}
#endif /* WIN32 */
#endif /* INSTR_TIME_H */
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