Re: [tlug] Xen and SMP

[Masanori ITOH <kgd00742@example.com>]

Hi Curt,

There were greate improvements between Xen 2.x and 3.0, so
I recommend you would try at least Xen 3.0.4 based Live CD.
I saw similar problems till Xen 3.0.3 (bundled in RHEL5 Beta2).

At this moment, a good choice would be XENOPPIX, I think.
  http://unit.aist.go.jp/itri/knoppix/xen/
  http://unit.aist.go.jp/itri/knoppix/xen/index-en.html

I'm not sure if Xen 3.1 based Line CDs are available or not...


Regards,
Masanori

From: Curt Sampson <cjs@example.com>
Subject: [tlug] Xen and SMP
Date: Fri, 11 Jan 2008 20:25:04 +0900

> I've been once again poking a bit at xen, and I'm curious as to its SMP
> behaviour. I booted up the Xen 2.5 live CD on a dual-core AMD system,
> and it appeared to me, according to the monitor display, to assign
> domains to either one or the other CPU, and then just stick them there.
> In my case, domains 0 and 3 were on CPU 0, and 1, 2 and 4 were on CPU 1.
> I then started up "while true; do true; done" on 1, 2 and 4 that started
> eating up lots of CPU on those machines, but all three domains stayed
> on CPU 1, getting about 1.6s each out of every 5s, and doms 0 and 2 sat
> there barely ticking, as expected. Starting the same loop on dom 3 found
> it getting about 5/5s, a rather unfair share!
> 
> This was Xen2; does it not move a domain from one CPU to another after
> it's been started? I gather Xen3 does this (as well as providing
> multiple CPUs to domains); does that compensate for it otherwise (so I
> hear) being somewhat slower?
> 
> cjs
> -- 
> Curt Sampson       <cjs@example.com>        +81 90 7737 2974   
> Mobile sites and software consulting: http://www.starling-software.com