Date: Mon, 28 Feb 2005 12:50:42 -0600 From: Dan Nelson <dnelson@allantgroup.com> To: Jeff Behl <jbehl@fastclick.com> Cc: freebsd-stable@freebsd.org Subject: Re: vmstat/iostat/top all fail to report CPU usage Message-ID: <20050228185042.GH8778@dan.emsphone.com> In-Reply-To: <422366DE.6020001@fastclick.com> References: <422366DE.6020001@fastclick.com>
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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@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
--
Dan Nelson
dnelson@allantgroup.com
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