Provided by: systemtap-doc_2.3-1ubuntu1.4_all 

NAME
function::gettimeofday_us - Number of microseconds since UNIX epoch
SYNOPSIS
gettimeofday_us:long()
ARGUMENTS
None
DESCRIPTION
This function returns the number of microseconds since the UNIX epoch.
SystemTap Tapset Reference March 2016 FUNCTION::GETTIMEOFD(3stap)