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SubjectRe: [OFFTOPIC] Re: K7 SMP
On Sun, May 02, 1999 at 12:10:46AM +0100, Paul Jakma wrote:
> In unix the kernel runs in process context..
>
> that i knew. so a process can trap to kernel mode via a syscall on
> cpu1 and hence the kernel runs on that cpu. i grok that.
>
> So the kernel ran on both cpus, but two copies of the kernel
> could not run at one (except when doing some trivial things). All
> the int's were processes by cpu0.
>
> afaik, the scheduler is called by the timer interrupt, right? so if
> the timer int is only delivered to cpu0, how can a scheduler hand
> over control to a process to run on cpu1, when the scheduler can't
> run on cpu1.
>
> i'd be glad if you could fill me in on what i'm missing.

The IPI, see other mail. CPU0 can send IPIs to the other to signal
rescheduling.

--
Dipl.Phys. Kurt Garloff <kurt@garloff.de> [Wuppertal, FRG]
Garloff Linux System Development [Linux-ix86,-axp, DUX]
Plasma physics, high perf. computing [Linux SCSI driver: DC390]
PGP key: see mailheader / key servers
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