Difference in stepping numbers?

[Daniel Rock]

Steve Kargl schrieb:
> Anyone know what the difference between stepping=8 and a stepping=10
> opteron processors?  When I purchased the processors I never noticed
> the different values because dmesg reports only the cpu info for the
> first processor, cpu0, which was stepping=8 in my case.
> 
> I've recently experienced segfaults and signal 10s during builds of
> the GCC source tree.  I narrowed the problem down to a possible problem
> with one of the cpus.  Well, I yanked cpu0 with stepping=8 and moved
> cpu1 with stepping=10 into the location of cpu0.  Booting a UP kernel
> revealed:
> 
> CPU: AMD Opteron(tm) Processor 248 (2194.48-MHz K8-class CPU)
>   Origin = "AuthenticAMD"  Id = 0xf5a  Stepping = 10
>   Features=0x78bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,
>   PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2>
>   AMD Features=0xe0500800<SYSCALL,NX,MMX+,LM,3DNow+,3DNow>
> 
> At the moment, I have not been able to generate a signal 10 or 11
> under fairly heavy load on cpu with stepping=10.

stepping = 8		==> C0 stepping
stepping = 10		==> CG stepping

according to AMD docs:

http://www.amd.com/us-en/Processors/TechnicalResources/0,,30_182_739_9003,00.html

26094		BIOS and Kernel Developer's Guide, section 12.8
25759		Revision Guide, page 8

mixed revisions are supported from C0 onwards.

Have you checked your BIOS (latest)?

The revision guide also contains a list of differences and fixes between the 
different steppings.


Daniel