Strange CPU graph (sawfoothed)

[ukman]

Hello,

I installed ESXi 4.1 on my server (Intel S5520HCR Xeon 5607 4 Cores). I installed Windows XP SP3 as guest OS.

Now I'm analyzing performance and I see strange CPU graph (see attached image). It's sawfoothed but nobody is connected to guest OS. CPU indicator within guest OS is almost freezed (zero). So what is going on? Any Ideas?

PS I played with numbers of vCPU, removed all optional devices (CD, Floppy, USB) but graph is the same.

[res03yzp]

I've ran into the same situation. I use Quest vFoglight to monitor VMs. Occassionally I get warnings in regards to high interrupts. Troubleshooting interrupts is not an easy task. I looked on the Internet and found a good link which has helped me in several occassions.

Try this....

http://blogs.technet.com/b/markrussinovich/archive/2008/04/07/3031251.aspx

[ukman]

In my case I discovered that CPU graph goes down right after loging in VSphere Client Console. I decided the problem is in waiting loging screen. So I added autologin for Windows XP and now it's ok for me but It's really misunderstandable for me why it eats CPU.