Re: [Condor-users] Is there a way to create a slot per a core (the goal is not to share the core cache between different jobs)

[Todd Tannenbaum <tannenba@xxxxxxxxxxx>]

On 4/27/2012 11:20 AM, Val Giner wrote:
> Tom,
>
> Thank you, I'll try that.
>
> BTW, in case it is known, when you are saying "talk ... about ... not
> working correctly" was that about particular versions? We have a few
> different versions working on more than one pool.
>
> Thanks,
> Val

Hi Val -

The recently discussed COUNT_HYPERTHREAD_CPUS issue is related to 
platform, not version.  Specifically, it was not working on Windows 
systems.  If you are running on Linux, you should be fine.  If you are 
on Windows, you will want to use NUM_CPUS as a workaround as Thomas 
suggested until we fix the problem on Windows, which will hopefully be 
for the next release
[ for details see
   https://condor-wiki.cs.wisc.edu/index.cgi/tktview?tn=1721  ]

p.s. you may also be interested in the ENFORCE_CPU_AFFINITY setting in 
the config file if you really want to isolate caches across slots - of 
course be aware you may pay a performance penalty... :

ENFORCE_CPU_AFFINITY
    A boolean value that defaults to False. When False, the affinity of 
jobs and their descendants to a CPU is not enforced. When True, Condor 
jobs and their descendants maintain their affinity to a CPU. When True, 
more fine grained affinities may be specified with SLOT<N>_CPU_AFFINITY.

SLOT<N>_CPU_AFFINITY
    A comma separated list of cores to which a Condor job running on a 
specific slot given by the value of <N> show affinity. Note that slots 
are numbered beginning with the value 1, while CPU cores are numbered 
beginning with the value 0. This affinity list only takes effect if 
ENFORCE_CPU_AFFINITY = True.

regards,
Todd

> On 4/27/2012 12:03 PM, Thomas Luff wrote:
> > Hi Val,
> >
> > Try setting COUNT_HYPERTHREAD_CPUS=False in your config file, this
> > should tell condor not to create job slots for virtual cores.
> >
> > There has been a bit of talk recently about it not working correctly
> > though so you might need to manually override it by settings NUM_CPUS
> > = 4 (or however many slots you require)
> >
> > Tom
> > ________________________________________
> > From: condor-users-bounces@xxxxxxxxxxx
> > [condor-users-bounces@xxxxxxxxxxx] On Behalf Of Val Giner
> > [valginer@xxxxxxxxxxxxxxxx]
> > Sent: 27 April 2012 16:45
> > To: condor-users@xxxxxxxxxxx
> > Subject: [Condor-users] Is there a way to create a slot per a core
> > (the goal is not to share the core cache between different jobs)
> >
> > Hello everyone,
> >
> > Does any one know whether there is a way to configure Condor on
> > multi-core Linux servers in such a way that there is only one slot per
> > core exists?
> >
> > My goal is to make sure that core caches are not shared between
> > different jobs.
> >
> > E.g., if there are two "physical treads" (hyper-threads) per a core and
> > there is a slot per the 'physical thread', the slots could be allocated
> > to two different jobs, which means they are going to share the same
> > cache.
> >
> > If I am making a mistake somewhere, please correct me
> >
> > --
> > Thanks,
> > Val
> >
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--
Todd Tannenbaum <tannenba@xxxxxxxxxxx> University of Wisconsin-Madison
Center for High Throughput Computing   Department of Computer Sciences
Condor Project Technical Lead          1210 W. Dayton St. Rm #4257
Phone: (608) 263-7132                  Madison, WI 53706-1685