Date: Sat, 05 Jun 1999 08:56:48 -0400 From: "Danny J. Zerkel" <dzerkel@columbus.rr.com> To: freebsd-stable@freebsd.org Subject: Re: kern/10411: top, vmstat, iostat show 0% cpu idle & usage on SMP system Message-ID: <37591E90.2FD85193@columbus.rr.com>
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Joe,
Do you have apm configured in your kernel? If so, try:
device apm0 at isa? flags 0x20
So far, this seems to correct it.
When I started digging around, I found that the stat clock had been
disabled.
The only thing that can disable it is apm, but the test looks backwards
to me:
*** /usr/src/sys/i386/isa/clock.c:
line 946:
cpu_initclocks()
{
int diag;
#ifdef APIC_IO
int apic_8254_trial;
#endif /* APIC_IO */
if (statclock_disable) {
/*
* The stat interrupt mask is different without the
* statistics clock. Also, don't set the interrupt
* flag which would normally cause the RTC to generate
* interrupts.
*/
stat_imask = HWI_MASK | SWI_MASK;
rtc_statusb = RTCSB_24HR;
} else {
/* Setting stathz to nonzero early helps avoid races. */
stathz = RTC_NOPROFRATE;
profhz = RTC_PROFRATE;
}
The problem seems to be that the statclock gets disabled if
statclock_disable
ISN'T set. My stathz was set to RTC_NOPROFRATE, which disables
collection
of stats.
> > After installing a MP kernel on my system I have noticed that the various
> > system utilities that display cpu usage all report 0.0% for everything.
> > The UP kernel does not have this problem and the MP kernel will work ok
> > briefly after rebooting, until I apply a load (such as starting X or
> > building a kernel).
>
> I am seeing this problem as well.
>
> ASUS P2B-DS, 2 x PII-400/512, disks moved from an HP Vectra XU/200 that
> worked just fine. I was running a mildly modified 3.0R on the Vectra
> which reported statistics correctly. Moving these to the P2B-DS broke,
> for reasons unknown, since I have other P2B-DS's on 3.0R which report
> statistics fine.
>
> I then upgraded the box to 3.1R since I thought maybe my mods were causing
> the problem, but it is still broken.
>
> Oddly, it appears to work fine in single-user, although I didn't play with
> it for more than a few minutes.
>
> More oddly, load average appears to report properly.
>
> If any bug whacker would like access to the box in question, it can be
> arranged easily enough (its a games machine). I'd sure like to see a fix
> for this.
>
> ... Joe
-- Danny J. Zerkel
dzerkel@columbus.rr.com
"Sursum ad Absurdum"
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