Does this not just bear out that the 'average' HS06 assigned by the sites to their farms is poor and/or that the spread of performance per core is wide on a given farm?
Martin.
--
Martin Bly
RAL Tier1 Fabric Manager
> -----Original Message-----
> From: Testbed Support for GridPP member institutes [mailto:TB-
> [log in to unmask]] On Behalf Of Steve Lloyd
> Sent: Saturday, June 04, 2011 1:51 PM
> To: [log in to unmask]
> Subject: Accounting continued
>
> Hi,
> I sent this to the PMB for discussion but some of you might be interested in
> it.
>
> I had a look at my benchmark results. The spread (= sdev/mean) in raw CPU
> times across all UK sites and machines is 29%. If I apply the average HS06 for
> each site obtained from Apel/ATLAS ('HS06 ATLAS') this increases to 38%. I
> haven't looked in any greater detail if the core gets smaller and the tails
> wider or anything like that (it wouldn't help us anyway). I also looked at the
> ATLAS production numbers. For April the spread in production CPU/job increases
> from 14% to 28% and production CPU/event from 22% to 33% if you scale by 'HS06
> ATLAS'. (These are averaged over sites not weighted by size). These bear out
> other observations made by ATLAS reported at a recent CMB/SPMB meeting that
> HS06 makes it worse than using raw CPU numbers. Basically correcting for HS06
> introduces ~25-30% noise into the measurements.
> However, if I use the ATLAS production CPU/event to derive a HS06 number
> ('HS06 Prod') i.e the production HS06/event should be constant and apply these
> to my benchmark results then the spread goes down from 29% to 23%. So
> basically if you derive your benchmark from actually running ATLAS code then
> it improves things (as you might hope) otherwise it makes it worse. So we
> should be using 'HS06 Prod' not 'HS06 ATLAS' (or nothing).
> Cheers Steve
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> + Steve Lloyd Queen Mary, University of London +
> + E-mail: [log in to unmask] School of Physics +
> + Phone: +44-(0)20-7882-5057 Mile End Road +
> + Fax: +44-(0)20-8981-9465 London E1 4NS, UK +
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
