The number of IPKTS and OPKTS in systat(1) is calculated by taking away the new total packets from the old total packets and dividing the result by the delay between refreshes (naptime). This calculation is performed in the macro UPDATE in if.c
I think the current description is inaccurate. ok? -mark Index: systat.1 =================================================================== RCS file: /cvs/src/usr.bin/systat/systat.1,v retrieving revision 1.88 diff -u -p -r1.88 systat.1 --- systat.1 13 Jan 2011 17:44:54 -0000 1.88 +++ systat.1 15 Jan 2011 13:46:36 -0000 @@ -501,8 +501,9 @@ The rest of the column breaks down the t by device basis. Only devices that have interrupted at least once since boot time are shown. .Pp -Below the Interrupts display is a summary of -total number of input packets and output packets for all interfaces. +Below the Interrupts display are +the average number of input and output packets per second +for all interfaces over the last refresh interval. .Pp Below the SWAPPING display and slightly to the left of the Interrupts display is a list of virtual memory statistics.