amd64/106194: 'systat -if' display bug

Alan Amesbury amesbury at
Fri Dec 1 19:40:13 PST 2006

>Number:         106194
>Category:       amd64
>Synopsis:       'systat -if' display bug
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-amd64
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Dec 02 03:40:03 GMT 2006
>Originator:     Alan Amesbury
>Release:        FreeBSD 6.1-RELEASE-p10 amd64
University of Minnesota
System: FreeBSD [REDACTED] 6.1-RELEASE-p10 FreeBSD 6.1-RELEASE-p10 #1: Thu Oct 12 14:14:54 CDT 2006 root@[REDACTED][REDACTED-NONGENERIC] amd64

This is a Dell PowerEdge 850 with HTT enabled.  The kernel's slightly
modified from GENERIC.

For large amounts of total data, FreeBSD/amd64's 'systat -if' changes units
and appears to report in bits.  This is an example screenshot:

                    /0   /1   /2   /3   /4   /5   /6   /7   /8   /9   /10
     Load Average   |||| 

      Interface           Traffic               Peak                Total

            lo0  in      0.000 KB/s          0.000 KB/s            9.832 KB
                 out     0.000 KB/s          0.000 KB/s            9.832 KB

           bge1  in     90.720 MB/s        101.412 MB/s     2903082122259256.000 b
                 out     0.000 KB/s          0.000 KB/s            0.244 KB

           bge0  in      0.025 KB/s          0.395 KB/s          286.027 MB
                 out     0.065 KB/s          0.451 KB/s          406.052 MB

The host in question has been up about 50 days, so it's hard to say exactly
when this display bug gets tickled.  I'm pretty sure it's displaying in bits
because a) the small "b" is a good hint, and more importantly b) there's no
way this host has seen 2600+TB in only 50 days.  362885265282407 bytes (or
around 330TB) is a believeable number, however.

Pass multiple terabytes through an interface.  Watch systat's counter.
I'm not sure, but I think this might have something to do with the stuff
around line 123 of

	src/usr.bin/systat/ifstat.c,v 1.2 2004/03/09 11:57:27 dwmalone Exp

The FreeBSD/i386 version doesn't exhibit this behavior, but the counter
appears to simply wrap at 4GB anyway.  I suspect that's a limitation of
the architecture, though.

Please let me know if you need additional information.

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