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Re: [Condor-users] How to filter out hyperthreading CPU cores
- Date: Tue, 08 Nov 2011 22:48:42 -0500
- From: Matthew Farrellee <matt@xxxxxxxxxx>
- Subject: Re: [Condor-users] How to filter out hyperthreading CPU cores
I don't know specifically, but you can run "env
_CONDOR_TOOL_DEBUG=D_FULLDEBUG condor_config_val -debug NUM_CPUS" to get
a look at how condor is detecting the number of CPUs.
On 10/21/2011 08:21 AM, Hermann Fuchs wrote:
has no effect. Still all virtual hyperthreaded cores show up.
works as expected.
However I would prefer a more automated way of detection.
Do you have any idea why COUNT_HYPERTHREAD_CPUS=FALSE could not work?
On this machine Ubuntu 11.04 64bit is employed.
On Fri, 2011-10-21 at 07:31 -0400, Matthew Farrellee wrote:
On 10/21/2011 04:38 AM, Hermann Fuchs wrote:
In our condor cluster we have several workstations configured to use
hyperthreading (e.g. virtual CPU cores from INTEL CPUs).
Condor seems to recognise virtual hyperthreaded CPU cores as real
and evenly divides recources.
For example a workstation with a four core Intel CPU would then
as an eight core workstation, which we would like to avoid.
We do not want to use such virtual CPU cores but can not enforce
hardware sided (e.g in the BIOS) deactivation. Is there a way that
condor somehow "filters" them out and announces only real CPU cores?
Can condor distinguish real cores from virtual ones?
I suppose manually declaring 4 CPU cores may not work because all 4
declared cores might be running on virtual cores...
You could configure NUM_CPUS=4, but try COUNT_HYPERTHREAD_CPUS=FALSE
This macro controls how Condor sees hyper threaded processors.
set to True (the default), it includes virtual CPUs in the default
of NUM_CPUS. On dedicated cluster nodes, counting virtual CPUs can
sometimes improve total throughput at the expense of individual job
speed. However, counting them on desktop workstations can interfere
interactive job performance.