Re: Re: Poor performance on HVM (kernbench)

[Gianluca Guida <gianluca.guida@eu.citrix.com>]

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Hi,

Gianluca Guida wrote:
> Todd Deshane wrote:
>> Xen 3.3 should be an improvement with shadow3 right?

I made a few test, in an amd64 kernel, with shadow2 and shadow 3.

Results attached. What you can see is that in 1 vcpu environment the two 
system compare very well (with shadow3 being 1.5% faster that shadow2, 
system time being much lower). It's disturbing that in 2 vcpus, instead, 
the shadow2 is about 11% faster. I'll try to look at that and make the 
shadow3 algorithm a bit more linux-friendly but, in general, I don't 
think that the slow down was due *only* to shadow3.

Was it a 32bit guest? PAE?

Thanks,
Gianluca


1 vcpu, shadow2

Thu Sep 11 14:09:14 EDT 2008
2.6.18-4-amd64
Average Optimal load -j 4 Run (std deviation):
Elapsed Time 414.792 (0.4772)
User Time 303.276 (0.508409)
System Time 111.148 (0.592891)
Percent CPU 99.2 (0.447214)
Context Switches 25682.6 (146.046)
Sleeps 28827.8 (99.8884)


1 vcpu, shadow3

Thu Sep 11 13:16:23 EDT 2008
2.6.18-4-amd64
Average Optimal load -j 4 Run (std deviation):
Elapsed Time 408.948 (1.96799)
User Time 326.482 (0.553191)
System Time 81.184 (2.0058)
Percent CPU 99 (0)
Context Switches 25239.6 (205.305)
Sleeps 28995 (152.91)


2 vcpus, shadow2

Thu Sep 11 11:59:27 EDT 2008
2.6.18-4-amd64
Average Optimal load -j 8 Run (std deviation):
Elapsed Time 223.144 (0.709704)
User Time 314.844 (0.933852)
System Time 121.536 (1.46827)
Percent CPU 195.2 (0.447214)
Context Switches 27307.4 (249.907)
Sleeps 34875.6 (212.731)


2 vcpus, shadow3

Thu Sep 11 12:32:41 EDT 2008
2.6.18-4-amd64
Average Optimal load -j 8 Run (std deviation):
Elapsed Time 251.832 (1.27152)
User Time 368.878 (0.745366)
System Time 124.472 (1.15751)
Percent CPU 195.4 (0.547723)
Context Switches 28585.2 (135.509)
Sleeps 35620.4 (447.023)

[-- Attachment #2: kernbench.log --]
[-- Type: text/x-log, Size: 1141 bytes --]

1 vcpu, shadow2

Thu Sep 11 14:09:14 EDT 2008
2.6.18-4-amd64
Average Optimal load -j 4 Run (std deviation):
Elapsed Time 414.792 (0.4772)
User Time 303.276 (0.508409)
System Time 111.148 (0.592891)
Percent CPU 99.2 (0.447214)
Context Switches 25682.6 (146.046)
Sleeps 28827.8 (99.8884)


1 vcpu, shadow3

Thu Sep 11 13:16:23 EDT 2008
2.6.18-4-amd64
Average Optimal load -j 4 Run (std deviation):
Elapsed Time 408.948 (1.96799)
User Time 326.482 (0.553191)
System Time 81.184 (2.0058)
Percent CPU 99 (0)
Context Switches 25239.6 (205.305)
Sleeps 28995 (152.91)


2 vcpus, shadow2

Thu Sep 11 11:59:27 EDT 2008
2.6.18-4-amd64
Average Optimal load -j 8 Run (std deviation):
Elapsed Time 223.144 (0.709704)
User Time 314.844 (0.933852)
System Time 121.536 (1.46827)
Percent CPU 195.2 (0.447214)
Context Switches 27307.4 (249.907)
Sleeps 34875.6 (212.731)


2 vcpus, shadow3

Thu Sep 11 12:32:41 EDT 2008
2.6.18-4-amd64
Average Optimal load -j 8 Run (std deviation):
Elapsed Time 251.832 (1.27152)
User Time 368.878 (0.745366)
System Time 124.472 (1.15751)
Percent CPU 195.4 (0.547723)
Context Switches 28585.2 (135.509)
Sleeps 35620.4 (447.023)

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