Re: IO on guest is 20 times slower than host

Kurt Yoder
2009-03-27T14:10:57Z

sorry to keep replying to myself:

>>> Kurt Yoder wrote:

<snip>

>
>
> So clearly there is something odd going on with the first one. It looks
> like it's CPU-bound, and this is throttling the IO?

slow guest cpu information:

processor : 0
vendor_id : AuthenticAMD
cpu family : 6
model : 2
model name : QEMU Virtual CPU version 0.9.1
stepping : 3
cpu MHz : 2612.149
cache size : 512 KB
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx lm 3dnowext 3dnow up
nopl pni svm
bogomips : 5224.29
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:

slow host cpu information, core 1 of 16:

processor : 0
vendor_id : AuthenticAMD
cpu family : 16
model : 4
model name : Quad-Core AMD Opteron(tm) Processor 8382
stepping : 2
cpu MHz : 2611.998
cache size : 512 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
apicid : 0
initial apicid : 0
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 mmxext fxsr_opt
pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl pni monitor
cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a
misalignsse 3dnowprefetch osvw ibs skinit wdt
bogomips : 5223.97
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

fast guest cpu information:

processor : 0
vendor_id : AuthenticAMD
cpu family : 6
model : 2
model name : QEMU Virtual CPU version 0.9.1
stepping : 3
cpu MHz : 2792.466
cache size : 512 KB
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx lm up nopl pni
bogomips : 5584.93
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:

fast host cpu information, core 1 of 16:

processor : 0
vendor_id : AuthenticAMD
cpu family : 15
model : 65
model name : Dual-Core AMD Opteron(tm) Processor 8220
stepping : 3
cpu MHz : 2792.573
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
apicid : 4
initial apicid : 0
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 nopl pni cx16 lahf_lm cmp_legacy svm
extapic cr8_legacy
bogomips : 5585.14
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

-Kurt