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#1 2011-01-17 18:45:44

Baraclese
Member
Registered: 2008-05-28
Posts: 48

only one CPU core recognized [solved]

For some reason the kernel only recognizes one CPU core out of two. I'm not completely sure at which kernel upgrade it disappeared but it is gone in 2.6.36 and 2.6.37. I know it was still there in september 2010 and earlier. I'm using a x86-64 kernel.

cat /proc/cpuinfo:
processor    : 0
vendor_id    : AuthenticAMD
cpu family    : 16
model        : 6
model name    : AMD Athlon(tm) II X2 245 Processor
stepping    : 2
cpu MHz        : 2913.253
cache size    : 1024 KB
fpu        : yes
fpu_exception    : yes
cpuid level    : 5
wp        : yes
flags        : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc up rep_good nopl nonstop_tsc extd_apicid pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt npt lbrv svm_lock nrip_save
bogomips    : 5828.27
TLB size    : 1024 4K pages
clflush size    : 64
cache_alignment    : 64
address sizes    : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

Motherboard is: Gigabyte MA770T-UD3P. I use the latest bios.

I have tried adding the kernel options "acpi=off noacpi apic=off noapic" as to the suggestion of a ubuntu bug report in launchpad but it didn't help. I also disabled ACPI in the bios but I'm still limited to one cpu core.

Any ideas?

[SOLVED]
I just doublechecked the BIOS settings and it had the CPU Core Control set to manual and one core was disabled. I set it to auto again and now both cores are recognized correctly. I don't recall ever touching this setting but at least it works now. Maybe a bios update actually changed the setting or (more probable) a friend of mine.

Last edited by Baraclese (2011-01-17 19:01:02)

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