Re: AMD vs. Intel
On Sun, Apr 11, 2004 at 10:30:39PM +0200, martin f krafft wrote:
> also sprach Henrique de Moraes Holschuh <hmh@debian.org> [2004.04.09.1949 +0200]:
> > It won't hurt. But nmi_watchdog is only for usermode and
> > kernemode hangs. The NMI watchdog is useless against nasty bugs
> > (hw or sw) that make the hardware unstable.
>
> Yes, I have just discovered that.
>
> (Note that my new thread is about a different machine. I can't try
> the stuff you suggested until Wednesday, when I get back to Zurich.
>
> > I get about 101 NMIs per second on each CPU using nmi_watchdog=1.
> > HZ=100 in this machine, I suppose... This is a not-really-SMP
> > machine, with a single P4 HT processor.
>
> related, but not to the thread: what's that HZ stuff? I assumed it
> to be something like Hertz, but I could be wrong. However, ever
> since I switched to the 2.6 kernel, I get the "Wrong HZ, was 67;
> should be 100" or something like that messages occasionally.
>
HZ is the number of jiffies in a second in the kernel (a value for
kernel time).
In 2.4 under i386 platforms it is 100, it 2.6 under i386 it was changed
to 1000 and a new value called USER_HZ was introduced for converting
kernel time to usermode time for programs that use hardcoded values,
although jiffies still slips through in several proc interfaces.
> > The software watchdog will reboot your machine (and AFAIK it might
> > very well be using NMIs to do it, too). If you can use a chipset
> > watchdog, however, that's much better (e.g. the TCO timers in most
> > Intel systems, and _especially_ the IPMI watchdog in servers with
> > a baseboard controller worth something).
>
> I'll think about it. How much are these hardware watchdogs, and
> which one would you recommend?
>
> --
> Please do not CC me when replying to lists; I read them!
>
> .''`. martin f. krafft <madduck@debian.org>
> : :' : proud Debian developer, admin, and user
> `. `'`
> `- Debian - when you have better things to do than fixing a system
>
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