Re: [Xen-users] Xen Performance

Luke S Crawford
Sat, 30 May 2009 20:05:09 -0000

Peter Booth <peter_booth@mac.com> writes:
> One real world example:
> native Linux:  		page response times of (  400ms/150ms)
> [mean/standard  deviation]
> Xen VM:			page response times of (  700ms/3.5s)
> [mean/standard  deviation]
>
> In this scenario, we have mean response times that are almost 100%
> worse, and the 90th percentile is 1000% worse.

Yeah, but if your average native times are 400ms, you are very likely
already hitting swap and experiencing what I would call unacceptable
performance.  It''s no suprise that swap on a shared device is going to
be
slower than a non-shared swap.

Hm.  unless that xen vm is on a xen box doing nothing else, in which case
the results whould suprise me quite a lot (unless you were using HVM mode
or had less ram in the xen vm than in the native box)