Possible reasons for high CPU load of taskmgr.exe process on VM?

Question

On a VMware virtual machine which has severe performance problems I can see a constant average of 20+ percent CPU load for the TASKMGR.EXE (task manager) process. The apps running on this server have lower load, around 4 to 10 percent average. The VM is running Windows 2003 Server Standard with 3.75 GB assigned RAM. I suspect that the task manager CPU load has something to do with other VM instances on the VMWare server but could not see a similar value on internal ESXi systems (the problematic VM runs in the customers IT).

Solution 1

I had similar symptoms, not on a VM but a Win7 Laptop. Taskmgr.exe and other processes (like Winmerge.exe) were taking 13% of cpu (one out of 8). The issue was temporarily alleviated by restart, so I was doing that a lot.

After long time investigating it, I figured that that Webroot Secure Anywere (software for virus and other types of protection) WRSA.exe was the culprit. Once I terminated that process, everything started to be fast again like magic! Not sure yet what to use instead of Webroot for protection.

Solution 2

Well, what if you just quit the taskmanager? :-)

Every time I've seen ridiculous values for the task manager load it turned out to be swapping on the VM host due to memory shortage. Check your memory statistics on the host, especially the values of assigned and used memory and the swap used.

Solution 3

The performance on a virtualization server should be assessed first on the physical server, then on the VMs.

Inside the VM the time calculations are not accurate, especially if you over-comit the VCPUs.

Also the CPU time spend in system time could affect the performance very badly. Even a 10% could double the response time of a VM even if the CPU in total is less than 15% used.

Check if you are not over-commitning the memory and the host server is not swapping. This will flush your performance down to the drain. Make sure the VMware tools are installed and the paravirtualization (direct I/O, baloon) drivers are running.

Comments

[user9517]

I have removed your VMware tag as VMware is a company. Please consider adding a product specific tag which can be found as vmware-product.

[eagle]

This is what I tried: using the Performance Monitor to monitor the total CPU load, I can see the base CPU load of 20-22% while the taskmanager is running. If I close the taskmanager, the Performance Monitor also drops to almost zero. It looks like the taskmanager process consumes > 20% CPU load.