Re: Alpha Timekeeping - Hardware Questions

Matti Aarnio (matti.aarnio@sonera.fi)
Fri, 14 May 1999 13:56:44 +0300 (EEST)

....
> The only way frequency differences can be avoided is to use a common
> clock source across CPUs. This could either be the actual clock used as
> input to the CPU, or it could be a slower clock that is phase-locked to
> the CPU input clock.
>
> So the question remains: Do SMP Alpha CPUs have synchronized input clocks?

At older Laser and TurboLaser multiprocessor systems
all CPUs seem to be running at same clock, or one which
is in PLL lock to some system wide distributed reference.

See DEC Technical Journal stories about 4100 system.

http://www.digital.com/DTJO00/

I have never heard of actual instances of multiprocessor systems
where processors run at different clock speeds, even if that were
technically possible by decoupling CPU internal operations, and
external system bus.

...
> B. D. Elliott bde@nwlink.com (Seattle)

/Matti Aarnio

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/