High Resolution Timestamp
[Operating System Dependent Functionality.]

Detailed Description

PJLIB provides High Resolution Timestamp API to access highest resolution timestamp value provided by the platform. The API is usefull to measure precise elapsed time, and can be used in applications such as profiling.

The timestamp value is represented in cycles, and can be related to normal time (in seconds or sub-seconds) using various functions provided.

Examples

For examples, please see:

Function Documentation

void pj_add_timestamp	(	pj_timestamp *	t1,
		const pj_timestamp *	t2
	)

Add timestamp t2 to t1.

Parameters:

	t1	t1.
	t2	t2.

void pj_add_timestamp32	(	pj_timestamp *	t1,
		pj_uint32_t	t2
	)

Add timestamp t2 to t1.

Parameters:

	t1	t1.
	t2	t2.

int pj_cmp_timestamp	(	const pj_timestamp *	t1,
		const pj_timestamp *	t2
	)

Compare timestamp t1 and t2.

Parameters:

	t1	t1.
	t2	t2.

Returns:: -1 if (t1 < t2), 1 if (t1 > t2), or 0 if (t1 == t2)

pj_uint32_t pj_elapsed_cycle	(	const pj_timestamp *	start,
		const pj_timestamp *	stop
	)

Calculate the elapsed time in 32-bit cycles. This function calculates the elapsed time using highest precision calculation that is available for current platform, considering whether floating point or 64-bit precision arithmetic is available. For maximum portability, application should prefer to use this function rather than calculating the elapsed time by itself.

Parameters:

	start	The starting timestamp.
	stop	The end timestamp.

Returns:: Elapsed time in cycles.

See also:: pj_elapsed_usec(), pj_elapsed_time(), pj_elapsed_nanosec()

pj_uint32_t pj_elapsed_msec	(	const pj_timestamp *	start,
		const pj_timestamp *	stop
	)

Calculate the elapsed time as 32-bit miliseconds. This function calculates the elapsed time using highest precision calculation that is available for current platform, considering whether floating point or 64-bit precision arithmetic is available. For maximum portability, application should prefer to use this function rather than calculating the elapsed time by itself.

Parameters:

	start	The starting timestamp.
	stop	The end timestamp.

Returns:: Elapsed time in milisecond.

See also:: pj_elapsed_time(), pj_elapsed_cycle(), pj_elapsed_nanosec()

pj_uint32_t pj_elapsed_nanosec	(	const pj_timestamp *	start,
		const pj_timestamp *	stop
	)

Calculate the elapsed time in 32-bit nanoseconds. This function calculates the elapsed time using highest precision calculation that is available for current platform, considering whether floating point or 64-bit precision arithmetic is available. For maximum portability, application should prefer to use this function rather than calculating the elapsed time by itself.

Parameters:

	start	The starting timestamp.
	stop	The end timestamp.

Returns:: Elapsed time in nanoseconds.

See also:: pj_elapsed_time(), pj_elapsed_cycle(), pj_elapsed_usec()

pj_time_val pj_elapsed_time	(	const pj_timestamp *	start,
		const pj_timestamp *	stop
	)

Calculate the elapsed time, and store it in pj_time_val. This function calculates the elapsed time using highest precision calculation that is available for current platform, considering whether floating point or 64-bit precision arithmetic is available. For maximum portability, application should prefer to use this function rather than calculating the elapsed time by itself.

Parameters:

	start	The starting timestamp.
	stop	The end timestamp.

Returns:: Elapsed time as pj_time_val.

See also:: pj_elapsed_usec(), pj_elapsed_cycle(), pj_elapsed_nanosec()

pj_uint32_t pj_elapsed_usec	(	const pj_timestamp *	start,
		const pj_timestamp *	stop
	)

Calculate the elapsed time in 32-bit microseconds. This function calculates the elapsed time using highest precision calculation that is available for current platform, considering whether floating point or 64-bit precision arithmetic is available. For maximum portability, application should prefer to use this function rather than calculating the elapsed time by itself.

Parameters:

	start	The starting timestamp.
	stop	The end timestamp.

Returns:: Elapsed time in microsecond.

See also:: pj_elapsed_time(), pj_elapsed_cycle(), pj_elapsed_nanosec()

pj_status_t pj_get_timestamp ( pj_timestamp * ts )

Acquire high resolution timer value. The time value are stored in cycles.

Parameters:

High resolution timer value.

Returns:: PJ_SUCCESS or the appropriate error code.

See also:: pj_get_timestamp_freq().

pj_status_t pj_get_timestamp_freq ( pj_timestamp * freq )

Get high resolution timer frequency, in cycles per second.

Parameters:

freq

Timer frequency, in cycles per second.

Returns:: PJ_SUCCESS or the appropriate error code.

void pj_set_timestamp32	(	pj_timestamp *	t,
		pj_uint32_t	hi,
		pj_uint32_t	lo
	)

Set timestamp from 32bit values.

Parameters:

	t	The timestamp to be set.
	hi	The high 32bit part.
	lo	The low 32bit part.

void pj_sub_timestamp	(	pj_timestamp *	t1,
		const pj_timestamp *	t2
	)

Substract timestamp t2 from t1.

Parameters:

	t1	t1.
	t2	t2.

void pj_sub_timestamp32	(	pj_timestamp *	t1,
		pj_uint32_t	t2
	)

Substract timestamp t2 from t1.

Parameters:

	t1	t1.
	t2	t2.

pj_int32_t pj_timestamp_diff32	(	const pj_timestamp *	t1,
		const pj_timestamp *	t2
	)

Get the timestamp difference between t2 and t1 (that is t2 minus t1), and return a 32bit signed integer difference.

References pj_int32_t.

High Resolution Timestamp [Operating System Dependent Functionality.]

Detailed Description

Examples

Functions

Function Documentation

High Resolution Timestamp
[Operating System Dependent Functionality.]