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Please excuse me if this is a stupid question, however, I'm curious why I'm not seeing any clock speed differences when using fedora as a guest VM via KVM/QEMU.

Perhaps this is a rather dumb way of concluding such things, but when I do cat /proc/cpuinfo | grep MHz it's always the same and it's the base clock speed advertised by my xeons.

Is there some option I have to pass virsh to enable turbo boost?

This might be helpful:

[jflowers@console ~]$ sudo lshw -class processor*-cpu                     
   description: CPU
   product: Intel(R) Xeon(R) CPU E5-2630 v4 @ 2.20GHz
   vendor: Intel Corp.
   physical id: 400
   bus info: cpu@0
   version: pc-q35-2.3
   slot: CPU 0
   size: 2GHz
   capacity: 2GHz
   width: 64 bits
   capabilities: fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp x86-64 constant_tsc arch_perfmon rep_good nopl eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm rdseed adx smap xsaveopt
   configuration: cores=30 enabledcores=30 threads=1*-processor UNCLAIMED
   description: SCSI Processor
   product: Console
   vendor: Marvell
   physical id: 0.0.0
   bus info: scsi@7:0.0.0
   version: 1.01
   capabilities: removable
   configuration: ansiversion=5

And a different utility:

[jflowers@console ~]$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                30
On-line CPU(s) list:   0-29
Thread(s) per core:    1
Core(s) per socket:    30
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 79
Model name:            Intel(R) Xeon(R) CPU E5-2630 v4 @ 2.20GHz
Stepping:              1
CPU MHz:               2195.304
BogoMIPS:              4390.60
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              25600K
NUMA node0 CPU(s):     0-29
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon rep_good nopl eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm rdseed adx smap xsaveopt
comjf
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1 Answers1

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The speed shown in /proc/cpuinfo inside a guest is meaningless/irrelevant. Regardless of what it says there, the CPUs will run at whatever speed the host CPUs support. IOW, if your guest is doing something CPU intensive, you can rest assured it'll max out the host CPU causing the host kernel to ramp up host CPU speed to maximum possible when needed.

DanielB
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