sysclock

Date:: 02-06-2023

NAME

SYSCLOCK - Returns real-time clock value and number of wraps

SYNOPSIS

INTEGER icount, iwrap
CALL SYSCLOCK(icount, iwrap)

INTEGER(8) icount8, iwrap8
CALL SYSCLOCK_8(icount8, iwrap8)

IMPLEMENTATION

Cray Linux Environment (CLE)

DESCRIPTION

SYSCLOCK returns the same real-time clock count returned by the count argument to the Fortran 90 SYSTEM_CLOCK intrinsic subroutine.

Use the count_rate argument on the SYSTEM_CLOCK intrinsic subroutine to determine the clock rate for SYSCLOCK.

All arguments must be of default kind unless documented otherwise. The default kind is KIND=4 for integer arguments.

The real-time clocks on processing elements are not synchronized with each other. Therefore, a SYSCLOCK() value should not be compared to a previous SYSCLOCK() taken on a different processing element.

RETURN VALUES

icount returns the lower half of the 64-bit CPU timestamp counter for x86_64 processors. For AARCH64, this returns the CPU timestamp count.

iwrap returns the upper half of the 64-bit CPU timestamp counter for x86_64 processors. For AARCH64, this always returns 0.