Messages in this thread |  | | Date | Sun, 14 Oct 2001 13:50:50 -0700 (PDT) | From | Gerhard Mack <> | Subject | Re: SMP processor rework help needed |
| |
On 14 Oct 2001, Andi Kleen wrote:
> In article <000b01c154ee$1d6a2610$6400a8c0@it0>, > "Tommy Faasen" <tommy@vuurwerk.nl> writes: > > Hi, > > I have this unique situation where cpu 1 has less features (like fxsr) then > > cpu 0. > > I used to have such an AMP machine too: a dual PII-300 with one Katmai and one > Deschutes. It's technically a violation of the specs; the Intel SMP spec > requires that the non boot cpus need to have a superset of the features > of the boot CPU. One CPU died, so it is symmetric now. > > For most capabilities it should already work in 2.4 after hpa's cpu > set rewrite, but FXSAVE is unfortunately a bit of a special case because > it is used in the scheduler context switch and that is required early > in the initialization for SMP bootup and changing it would be very > intrusive. > > In the 2.2 SuSE kernel it was fixed instead by adding a new kernel > command line option nofxsave that overrides the FXSAVE bit on the first > CPU. That is ok because such setup is very rare and is only generated by > people who build their own boxes; and these should also know how to pass > kernel command line arguments.
This may sound like a dumb question but wouldn't simply swapping the CPUs have the same affect?
Gerhard
-- Gerhard Mack
gmack@innerfire.net
<>< As a computer I find your faith in technology amusing.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |