vmstat/iostat/top all fail to report CPU usage

[Jeff Behl]

Dan Nelson wrote:

>In the last episode (Feb 28), Jeff Behl said:
>  
>
>>as reported in bug: bin/60385
>>
>>this is still occurring in almost all of our systems, even those at 
>>stable, and is pretty major issue.  any known progress on this?  we're 
>>running ibm e325 servers. 
>>
>>FreeBSD www3 5.3-STABLE FreeBSD 5.3-STABLE #1: Tue Feb 15 10:09:17 PST 
>>2005    root at www3.cdn.sjc:/usr/obj/usr/src/sys/SMP  amd64
>>    
>>
>
>Here's the workaround I use on a machine here that loses its stat clock
>after a week or so of uptime.  Put this in /etc/crontab:
>
>#  Flaky clock.  Check it every 5 minutes.
>*/5     *       *       *       *       root    /usr/local/bin/fixrtc
>
>.. and this in /usr/local/bin/fixrtc:
>
>#! /bin/sh
>
># get the interrupt rate for the stat clock over one second
>getticks() {
>  ( vmstat -i ; sleep 1 ; vmstat -i ) |
>  awk '/rtc/ { if (sum) sum+=$3; else sum-=$3 } END { print sum }'
>}
>
>ticks=$(getticks)
>
># It should be firing at 128 hz.  If not, kick it
>if [ $ticks -lt 64 ] ; then
>  echo "Stat clock has died.  Attempting to reset."
>  echo
>  /etc/rc.d/ntpd stop
>  echo
>  /usr/sbin/ntpdate -b ntp.pool.org
>  echo
>  /etc/rc.d/ntpd start
>  echo
>  echo "RTC interrupt rate is now $(getticks)"
>fi
>
>
>  
>
excellent, thanks much Dan.  this does the trick nicely and will help a 
lot.  hopefully there'll be a commit for the real fix for 5.4.