[Beowulf] Opteron bug reported

Erwan Velu erwan at mandrakesoft.com
Wed Jun 23 09:16:34 PDT 2004

Le mer 23/06/2004 à 16:53, Douglas Eadline, Cluster World Magazine a
écrit :
> I just put a story up on ClusterWorld.com about a bug that has been found
> in the Opteron. I also collected some links about the bug. It seems
> to manifest itself under rare circumstances.
If you own some Opterons with more than 4Gb of memory, the MTRR are
sometimes not well set. So you can't setup correcty some WC (Write
Combining Areas).

A simple script could workaround that by unsetting the "Write Back" ones
and adding some WC.

After that, performances are back, WC accesses are ok :)
Erwan Velu
Linux Cluster Distribution Project Manager
Mandrakesoft 43 rue d'aboukir 75002 Paris
Phone Number : +33 (0) 1 40 41 17 94
Fax Number   : +33 (0) 1 40 41 92 00
OpenPGP key  : http://www.mandrakesecure.net/cks/ 

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