Re: Serious performance issues

[Tommi Virtanen <tv@tv.debian.net>]

Anthony Liguori wrote:
>> I tested the disk, it still transfers ~50MB/s. I don't seem to be
>> suffering from PIO mode. Also, things running from RAM cache are as
>> slow as from disk.
> What version of Xen is this?

2.0.4, as packaged for Debian by Adam Heath at
http://people.debian.org/~doogie/

> If you're running xen-unstable, try xen-2.0.x or vice versa.  Are you 
> absolutely positive that you've got enough memory allocated to dom0?  

As dom0 is my main environment, it gets almost all of the RAM.

title           Xen 2.6.10
root            (hd0,1)
kernel          /boot/xen.gz dom0_mem=917504
module          /boot/xen-linux-2.6.10+xen0 root=/dev/hda2 ro
module          /boot/initrd.img-2.6.10+xen0
savedefault
boot

> That you've got the proper IO chipset support built into the kernel?  

The config is pretty much identical between native linux and xen dom0.

> That you've really got tls disabled (if you just move tls after an app 
> has already launched using it it will still be using it until you 
> restart the app)?

I have rebooted many times since the move.

> These numbers seem too bad to be Xen's fault alone.  Do you have swap 
> enabled?  Is there a great deal of swap activity?

There's 2 gigs of swap with under 3 megabytes used, no blocks going in
or out.


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