Subject: Re: Multiprocessor with NetBSD ?
To: Greywolf <firstname.lastname@example.org>
From: Bill Sommerfeld <email@example.com>
Date: 06/06/2001 13:47:35
> + Is cpu0 always going to be the boot processor? If that's the case,
> how is it I've seen a Sun start on one processor and halt on
> another one?
1) netbsd is not solaris.
2) There isn't a 1:1 mapping between scsi bus address and device ids.
The first-attached "cpu0" device may not be the processor with
hardware id 0.
It seems to be common for quad pentium pro systems for the processor
at hardware id 3 to be the boot processor and be attached as cpu0.
3) support for hot-swappable cpu's will happen when someone sends me
4) Any cpu can call cpu_reboot(); what happens from that point on is
machine-dependant. Some hardware may require that the boot cpu halt
the machine; some might not.
> + When you say that all processors handle the clock interrupt, do
> you mean that they all trigger the clock interrupt at some point, or
> that they read it and update internal things accordingly? (I assume
> the latter, based on the premise that only the boot processor keeps
> the TODC updated.)
Each cpu requires a periodic timer interrupt for scheduler
housekeeping sorts of things (e.g., to notice when a process has
exceeded its timeslice and should be preempted).
On the master cpu, this timer interrupt also maintains the time-of-day