$WW,1$One jiffy is one time slice.  $LK,"Jiffies","MN:Jiffies"$ returns time slices since boot and takes longer to compute than $LK,"GetTimeStamp","MN:GetTimeStamp"$.

$LK,"ReadSysTimer","MN:ReadSysTimer"$ reads the timer ticks since boot.  It's not as fast as $LK,"GetTimeStamp","MN:GetTimeStamp"$.

Use $LK,"JIFFY_FREQ","MN:JIFFY_FREQ"$ to convert $LK,"Jiffies","MN:Jiffies"$.

Use $LK,"SYS_TIMER_FREQ","MN:SYS_TIMER_FREQ"$ to convert $LK,"ReadSysTimer","MN:ReadSysTimer"$.