[R] Hardware oddity - linux/windows
Prof Brian Ripley
ripley at stats.ox.ac.uk
Tue Sep 9 15:29:36 CEST 2003
Do you have an anti-virus software running? That's about what I see when
Sophos is switched on.
On 9 Sep 2003, michaell taylor wrote:
> I am trying to figure out why a new machine is running my R script so
> The script was developed on a Linux , dual 2.8 xeon processor machine
> with 4GB ram. On this machine, the script runs in about an hour (it
> creates lots of multilevel simulations). While running, 100% of a single
> processor (50% of dual processor) is used consistently during the entire
> run, about 800 MB of ram is utilized. Xeon hyperthread condition
> (on/off) seems not to matter to performance. While the script runs, I
> am using the "other" processor for miscellaneous emailing, editing, etc.
> Moving the script to a windows XP machine with nearly identical hardware
> configuration (2.8 dual xeon, 4.5 GB ram) the script takes nearly 2
> hours. Oddly, the maximum cpu load on this machine is 50% of a single
> processor (25% of dual processor) during the run - which seems
> consistent with the doubling of total processing time. While running
> this script, this machine does no other tasks whatsoever.
The last is very, very unlikely.
> Both machines have at least double the memory required for the task,
> both utilize fast scsi drives and all data is stored locally on the
> drive (no data on network drives). Moreover, being a simulated problem,
> very little data is read/written to drives during the process.
> Anyone have ideas as to why the Windows machine is so slow?
> Thanks in advance.
> Michaell Taylor
> R-help at stat.math.ethz.ch mailing list
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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