Date: Sat, 05 Jun 1999 15:49:29 -0700 From: "Andrew W. Flury" <aflury@nas.nasa.gov> To: "Danny J. Zerkel" <dzerkel@columbus.rr.com> Cc: freebsd-stable@FreeBSD.ORG, holtor@yahoo.com Subject: Re: kern/10411: top, vmstat, iostat show 0% cpu idle & usage on SMP system Message-ID: <199906052249.PAA13811@madrugada.nas.nasa.gov> In-Reply-To: Your message of "Sat, 05 Jun 1999 08:56:48 EDT." <37591E90.2FD85193@columbus.rr.com>
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FYI, this problem also exists if you have APM enabled in your BIOS setup but
not enabled in your kernel. Disabling it in the BIOS is one way to fix it
(it's enabled on ASUS P2B boards by default).
> 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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