Instability in Athlon64 X2 due to Usermode Speed Governor

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General Schvantzkoph

I've had some instability problems with my new A64 X2 4400+ system.
I've had a system crash and a kernel Make that failed with the error
message that stated that there was an irreproducible error which was
probably due to a hardware problem. On my console there was a number of
messages saying that there were K8 Powernow Out of Sync errors.

Aug 7 20:52:26 nimitz kernel: powernow-k8: error - out of sync, fid 0x2
0xe, vid 0x12 0xa

I've changed the speed governor to Performance on both CPUs so that the
processors will remain in sync and I haven't seen any problems since but
it hasn't been long enough to tell if this has really fixed the problem.

I'm running 32 bit FC3 with a custom 2.6.11.12 highmem SMP kernel (the
Redhat 2.6.12-1.1372_FC3 doesn't work on this system due to the broken
drivers for the nvsata and silsata drivers).

The system is an Athlon 64 X2 4400+ with 4G of RAM and an MSI K8N Neo4
platinum.

Has anyone else seen stability problems with the X2?
 
I've had some instability problems with my new A64 X2 4400+ system.
I've had a system crash and a kernel Make that failed with the error
message that stated that there was an irreproducible error which was
probably due to a hardware problem. On my console there was a number of
messages saying that there were K8 Powernow Out of Sync errors.

Aug 7 20:52:26 nimitz kernel: powernow-k8: error - out of sync, fid 0x2
0xe, vid 0x12 0xa

I've changed the speed governor to Performance on both CPUs so that the
processors will remain in sync and I haven't seen any problems since but
it hasn't been long enough to tell if this has really fixed the problem.

I'm running 32 bit FC3 with a custom 2.6.11.12 highmem SMP kernel (the
Redhat 2.6.12-1.1372_FC3 doesn't work on this system due to the broken
drivers for the nvsata and silsata drivers).

The system is an Athlon 64 X2 4400+ with 4G of RAM and an MSI K8N Neo4
platinum.

Has anyone else seen stability problems with the X2?

Wish I had one to test. Maybe by years end. Your message makes sense
though, assuming you were running cpufreq with auto scaling where each cpu
would scale according to load if powernow didn't keep them in sync. You
might want to just disable cpufreq and set them manually with userspace
and see how that works. This would appear to be a cpufreg problem since it
controls the powernow settings. Maybe there'a something in the
cpufreqd.conf for multi proccessors to avoid them but I don't recall
anything in the version I've got on kernel 2.6.11-6mdk.
 
Wish I had one to test. Maybe by years end. Your message makes sense
though, assuming you were running cpufreq with auto scaling where each cpu
would scale according to load if powernow didn't keep them in sync. You
might want to just disable cpufreq and set them manually with userspace
and see how that works. This would appear to be a cpufreg problem since it
controls the powernow settings. Maybe there'a something in the
cpufreqd.conf for multi proccessors to avoid them but I don't recall
anything in the version I've got on kernel 2.6.11-6mdk.

I've set both governors to performance which solves the problem because it
forces the highest speed. If I want to lower the frequency and have it
stick then I can just set them both to powersave, there isn't a heat or
noise issue because this is a server in another (air conditioned) room and
the cpu temps are low, 36C unloaded, 43C doing a make -j 2.

The the kernel won't load the ondemand governor for the X2 so I suspect
that the kernel writers already know that there is an issue changing the
clock speeds of the X2.
 
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