Re: [kvm-devel] performance with guests running 2.4 kernels (specifically RHEL3)

[David S. A. <da...@ci...>]

Avi Kivity wrote:
> 
> Okay, I committed the patch without the flood count == 5.
> 

I've continued testing the RHEL3 guests with the flood count at 3, and I
am right back to where I started. With the patch and the flood count at
3, I had 2 runs totaling around 24 hours that looked really good. Now, I
am back to square one. I guess the short of it is that I am not sure if
the patch resolves this issue or not.

If you want to back it out, I can continue to apply on my end as I
continue testing. A snapshot of kvm_stat -f 'mmu*' -l is attached for
two test runs with the patch (line wrap is horrible inline).

I will work on creating an ap that will stimulate kscand activity
similar to what I am seeing.


Also, in a prior e-mail I mentioned guest time advancing rapidly. I've
noticed that with the -no-kvm-pit option the guest time is much better
and typically stays within 3 seconds or so of the host, even through the
high kscand activity which is one instance of when I've noticed time
jumps with the kernel pit. Yes, this result has been repeatable through
6 or so runs. :-)

david