Tomasz Chmielewski wrote:
Avi Kivity schrieb:
Tomasz Chmielewski wrote:
Why do my guests show "Clocksource tsc unstable" on bootup?


Linux expects the tsc to be monotonic and to have a 1:1 correspondence with real time, which isn't easy to achieve with virtualization.

But the clocksource is kvm-clock, so why does the guest probe tsc at all?


Good question. I don't know what the answer is. Maybe the scheduler uses tsc for its internal clock.


I pasted a part of /proc/cpuinfo below.
I saw these with kvm-83 and kvm-84 (with cpufreq disabled, as it perhaps can matter).

processor       : 3
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 65
model name      : Dual-Core AMD Opteron(tm) Processor 2212
stepping        : 2
cpu MHz         : 2000.000
cache size      : 1024 KB
physical id     : 1
siblings        : 2
core id         : 1
cpu cores       : 2
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
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 rdtscp lm 3dnowext 3dnow rep_good pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
bogomips        : 3993.03
TLB size        : 1024 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management: ts fid vid ttp tm stc


This cpu indeed has unstable tsc, but disabling cpufreq should have fixed it.

Maybe we need to disable C-states as well?


--
error compiling committee.c: too many arguments to function

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