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

NAME
function::local_clock_us - Number of microseconds on the local cpu's clock
SYNOPSIS
local_clock_us:long()
ARGUMENTS
None
DESCRIPTION
This function returns the number of microseconds on the local cpu's clock. This is always monotonic
comparing on the same cpu, but may have some drift between cpus (within about a jiffy).
SystemTap Tapset Reference March 2016 FUNCTION::LOCAL_CLOC(3stap)