Re: [Xen-devel] JavaRMI and Xen problem

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

> I am facing a strange problem with Java RMI and Xen. I will describe the
> problem as well as the experimental results.

Yup, it's definitely a strange looking problem!

> Scenario1: Machine2 is booted with xen as the kernel

How much memory have you configured for dom0?  If it's less than the full 
allocation (e.g. if you are reserving space for other VMs) then the JVM / RMI 
Registry could be thrashing the swap device?

If it's not that then, as Ian said, some other network performance numbers 
(e.g. ttcp, or just ftp a large file across and calculate the bandwidth) 
would be interesting.

What version of Xen are you running on?  -stable, -testing or -unstable.  If 
you're running -unstable, what revision are you on?

Cheers,
Mark

> Scenario2: Machine2 is booted with Linux kernel (Xen is not involved at
> all)
>
> The client on Machine1 tries to look up the object that it needs to
> contact in the registry on Machine2. The object to be available in the
> RMI registry on Machine2 takes around 21 seconds.
>
>
>
> In scenario1 I am not starting any virtual machines. The service is
> available in Domain0 (Machine2). Nothing is changed except the kernel to
> boot. But, the results look strange. The Xen and Java RMI stuff looks
> very strange. The problem here is, on a Xen machine the Java object to
> be available in the RMI registry takes very long time. According to our
> experiments it shows that it is approximately 6 times slow. Is it normal
> with RMI-Xen?
>
> Can any body give pointers to this problem?
>
>
>
> Thanks,
>
> Sai
>
>
>
>
>
> Sai S. Dharanikota
>
> Intel GmbH
>
> Software & Solutions Group
>
> Hermuelheimer Strasse 8a
>
> 50321 Bruehl
>
> Germany
>
> Tel : +49 2232 209053

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