VMware Performance Community
mitchc
Contributor
Contributor

100% CPU utilization at 8 tiles

Hi All!

I'm seeing the vmmark workload peg all 8 of my CPUs. Is this normal? It seems like others have gotten much higher scores with similar horsepower. I'm scoring about a "9" with 8 tiles running, but the CPUs are all completely pegged out by around the time the 6th tile loads up. I have been playing with different advanced configuration settings in ESX (based on a sampling of the disclosure PDFs found here: http://www.vmware.com/products/vmmark/results.html ) as well as with adjusting the dbench delay period in VMMARK.CONFIG (tried moving from 50 to 10 secs) but nothing seems to help. My setup is ESX4u1 on a supermicro with 2x4 core Xeon 5450 for 8 total cores. 64GB of RAM. I feel like I'm missing something dumb: is it the fact that I am using an eval license? is it because hyperthreading is "inactive"? maybe some bios setting I should look for?

For storage I'm using 5 direct attached ioDrives, with which I have achieved over 100MByte/s randwrite at 4k block size on fileserver0 using the fio benchmark (and well over 600MByte/s randwrite at 1m blocksize.. both a bit higher for randread), and that should be per-drive.. so an aggregate of over 3GByte/s if I were to stripe them is theoretically possible.

I found a nifty way to capture performance stats and view them after the fact: "esxtop -b -d 60 -n 180 > stats.csv" grabs 3 hours worth of stats from the run, sampling at 1 minute intervals. The csv file can then be understood by perfmon.exe in my client0. Let me know if you'd like to see the csv file, or any other stats or files from my run.

thanks a lot!

Mitch.

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jamesz08
VMware Employee
VMware Employee

6-tiles is about the max that box would be able to handle. Xeon 5450 doesn't have Hyperthreading. There is a huge delta in performance betwen the Xeon 55xx and 54xx processors. The published Xeon 5460 results max at 6 or 7 tiles (look at the 8core/8thread reasults), the Xeon 5570 max out at 17 tiles (look at the 8core/16thread results)/.

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ePaulSG
Contributor
Contributor

Hi Mitch,

Just curious but are you using the vmxnet3 driver or any of the paravirtualization drivers for your systems? This might not be related but I have noticed some "odd" CPU performance characteristics when using those drivers. VMs talking to one another on the same host = CPU and network perf bad. VMs talking to one another across multiple ESX hosts = CPU and network perf good. I don't recall the actual adjustment or tweak, but it was something with the ESX kernel and network throughput that needed to be changed. I'll see if I can dig it up and post later on.

Paul

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