Re: 50% slowdown on 2 processor XEN 4.1.3 vs 1 processor system

[Harry Waddell <waddell%caravaninfotech.com@localhost>]

On Tue, 27 Nov 2012 00:09:32 -0600
"Cherry G. Mathew" <cherry.g.mathew%gmail.com@localhost> wrote:

> On 26 November 2012 03:00, Harry Waddell 
> <waddell%caravaninfotech.com@localhost> wrote:
> >
> > I just built a new server with 2 x E5-2630 processors and was comparing the
> > performance to a nearly identical xen server with 1 x E5-1660 processor and
> > found that on a per core basis, instead of being about 50% faster ( as one 
> > would expect from the clock speed given that the architecture is nearly 
> > identical ), the E5-1660 system is %300 faster, so I ran some benchmarks 
> > and started looking for a pattern.
> >
> > Both systems run NetBSD amd64 6.0-STABLE with xen 4.1.3. The 2
> > processor system is running only 1/2 as fast with the XEN3_DOM0 kernel
> 
> I hope you realise that NetBSD dom0 is not MP capable ?
> 
> -- 
> ~Cherry
> 

Not only do I know that, but I believe your name is next to that goal on the 
xen roadmap. ;-) I did however setup a 24 vcpu domU just to see if it worked, 
and I'm glad to say it did. 

Anyway, yes, all the performance measures I gathered were single threaded. 
"top" showed that only one cpu core was engaged. The followup email I sent 
earlier today with some sysbench results show that I'm only running single 
threaded tests. 

Please let me know if you think of any info I can supply or any tests I can 
run. 

HW