ESXi5: Help needed with asssigning all resources to 1 VM

[drfootz]

Hi!

For our office I've set up a homebrew ESXi box running vSphere 5. Hardware: Core i7 3820 (3.6gHz quadcore /w HT), 16gb ram, dual ssd; vSphere 5 free license.

=> I'm trying to assign all resources to a single VM: full memory (which works fine) and full CPU resources.

When running a benchmark on the VM (having 8 vCPU's, 1 phy x 8 cores) on 20+ threads, the system is only uses ~6gHz, or 16,6% per core. Running 'top -d 1' on the command line shows all 8 virtual cores are being maxed out, but in the vSphere console the load is minimal.

The performance in the VM is relatively poor when compared to the specs. My guess is the resource pool is holding back the performance, but i cannot assign more than 11700mhz to the pool/vm.

System overview

http://i36.tinypic.com/2ir3lep.png

Linux showing 100% load per core, but VMware only showing ~750mHz per core.

http://oi35.tinypic.com/x6engx.jpg

http://i36.tinypic.com/15mk9j5.png

11700mHz total cpu capacity?

http://i35.tinypic.com/ir2890.png

Can anyone help me with this issue? What am I overlooking?

If you need more information please let me know.

[Linjo]

What are the reasons for the benchmark?

Is the ESX just going to run 1 workload?

In the VM you have configured 8 vCPU:s but you only have 4 pCPU:s available, reduce it to 4vCPU:s and it probably runs better.

What about the drivers in the virtual machine? Are you running updated vmware tools and are you using pvscsi?

What hardware version is the virtual machine running?

Have you disabled all power management in bios and tuned it for max performance?

// Linjo

[drfootz]

Thank you kindly for your responses.

I've deleted the resourcepool and attached the VM directory to the host entry. This is how I initially installed it, but no difference. Putting the VM under full stress the host still only gets 25% utilized.

I've switched from 1x8 to 2x4 and 2x2, no difference (2x2 even slower performance). Hardwareversion is 8 of course, it's a fresh 5.1 install with a freshly made VM (debian squeeze).It seems as the VM is capped at 6gHz (out of 24).

Reason to do the benchmark was slow cpu performance. For example running a simple bash-based pi-calculation (time echo "scale=5000; a(1)*4" | bc -l) runs in ~30 seconds on a core2duo 2.66gHz, but on the i7 vm it takes more than twice as much time (both machines with no further cpu load).

More ideas?

[Linjo]

Not sure how you come to 24GHz? I thought you had 1 pCPU with 4 cores, is that incorrect?

If you are running vSphere 5.1 then you should use hardware version 9, righclick the VM and choose "Upgrade hardware version".

(This will probably not change the benchmark result though)

Did you try my other suggestions?

What about the drivers in the virtual machine? Are you running updated vmware tools and are you using pvscsi?

What hardware version is the virtual machine running?

Have you disabled all power management in bios and tuned it for max performance?

// Linjo

[Sreejesh_D]

1. Is there any reason for keeping resource pool? since you are going to assign the entire resources you dont need a resource pool and assoicated settings like reservation, limit etc.

2. Instead of creating a single vCPU with 8 cores create 2 vCPUs with 4 cores each.