Hi Stephen

If you have production and user jobs running in the same fairshare
slot then, yes, you'll certainly suffer here.

Most sites split the fairshare between atlas production and normal
atlas user jobs. Then Steve's jobs go into the user job fairshare and
don't get affected (as much) by running a lot of production. N.B. that
the ATLAS request to T2s is to split their share 50/50 between these
two activities.

Sites that support ATLAS analysis equally run into trouble if they get
a huge number of user jobs in and run out of fairshare here. Then even
the light bit of user level fairshare we do can't compensate Steve's
jobs enough if an inactive VO suddenly starts up and gets a very high
priority from maui. I did try and use max/min proc in maui to try and
reserve some slots to ensure that VOs got a certain minimum
throughput, even if their fairshare was consumed, but I wasn't able to
get it to work.

Sometimes we do fiddle with the fairshares on the fly if it seems that
their "fairness" has gone a bit screwy.

In the end, Steve's jobs are just a test and really you should not
worry about them timing out in the system. Providing service to the
ATLAS VO is what's more important, which TCD are certainly doing right
now.

That said... I confess we do allow Steve's jobs to run in the same
reserved slot that we have for ATLAS sgm, which lies idle most of the
time.

Cheers

Graeme


On Mon, Jan 26, 2009 at 6:12 PM, Stephen Childs <[log in to unmask]> wrote:
> Our site has loads of atlas production jobs running and so Steve's atlas
> tests end up being queued for ages. Looking at the results page, it appears
> that heavily-used atlas sites seem to pass the tests quite reliably. Do you
> reserve a slot for the UK atlas test jobs? Or is it acceptable that tests
> testing the ability to do analysis fail due to contention with production
> jobs?
>
> Stephen
> --
> Dr. Stephen Childs,
> Research Fellow, EGEE Project,    phone:                    +353-1-8961797
> Computer Architecture Group,      email:        Stephen.Childs @ cs.tcd.ie
> Trinity College Dublin, Ireland   web: http://www.cs.tcd.ie/Stephen.Childs
>



-- 
Dr Graeme Stewart              http://www.physics.gla.ac.uk/~graeme/
Department of Physics and Astronomy, University of Glasgow, Scotland
DEATH TO MEETINGS!