The arrow of time

Ivan Voras' blog

How much performance do you lose with VMWare?

I finally have a VMWare ESX 4 (vSphere 4) in production and it's time to see how much we lost this time in the name of greater flexibility. In short: the usual (which is a lot).

Here's what unixbench, a mostly single-process benchmark (all except shell scripts) can get on raw dual Xeon 5430 (2.6 GHz, 8 cores total, amd64 in all cases):

TEST                                        BASELINE     RESULT      INDEX

Dhrystone 2 using register variables 116700.0 15517961.7 1329.7
Double-Precision Whetstone 55.0 3503.0 636.9
Execl Throughput 43.0 2093.3 486.8
Pipe Throughput 12440.0 1258069.1 1011.3
Pipe-based Context Switching 4000.0 52388.3 131.0
Process Creation 126.0 3569.8 283.3
Shell Scripts (8 concurrent) 6.0 733.0 1221.7
System Call Overhead 15000.0 1011896.9 674.6

And here is the virtualized result:

                     INDEX VALUES            
TEST BASELINE RESULT INDEX

Dhrystone 2 using register variables 116700.0 15002297.7 1285.5
Double-Precision Whetstone 55.0 3511.2 638.4
Execl Throughput 43.0 512.6 119.2
Pipe Throughput 12440.0 1077539.8 866.2
Pipe-based Context Switching 4000.0 30414.4 76.0
Process Creation 126.0 641.1 50.9
Shell Scripts (8 concurrent) 6.0 111.3 185.5
System Call Overhead 15000.0 680753.7 453.8

As expected, anything involving a lot of syscalls or other context switches will suffer. This is mostly disk and network IO, but it's surprising how low the concurrent shell scripts test gets when the number of vCPUs increases.

On the other hand, it really *is* more convenient this way...

#1 Re: How much performance do you lose with VMWare?

Added on 2009-12-11T08:46 by nicholas wang

nice report, but i can't understand the mean that "RESULT" and "INDEX" column described. The result culomn that i thought the score higher is better, but what the index culomn?

#2 Re: How much performance do you lose with VMWare?

Added on 2010-07-01T01:59 by Ivan Voras

Performance index relative to baseline platform (for convenience, not really important otherwise).

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