| IDL with multiple processors [message #13717] |
Thu, 03 December 1998 00:00  |
David Schmidt
Messages: 6
Registered: January 1997
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Junior Member |
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We recently tested the speed of a non-graphical, numerical IDL code run
on two different Linux systems. The system with 2 350 MHz processors
and SDRAM was about the same speed or a bit slower than the system with
1 233 MHz processor and EDORAM.
Anyone else have performance problems/suggestions for multiprocessor
machines?
David
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| Re: IDL with multiple processors [message #13779 is a reply to message #13717] |
Mon, 14 December 1998 00:00  |
Martin Schultz
Messages: 515
Registered: August 1997
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Senior Member |
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Stein Vidar Hagfors Haugan wrote:
> In article <749m0g$875$1@agate.berkeley.edu>
> korpela@islay.ssl.berkeley.edu (Eric J. Korpela) writes:
>
>> I'm pretty sure that when using floating licences, every IDL process I
>> start checks out 10 licences regardless of which display they are running
>> on. It's only the static licenses that allow any number of processes to
>> be started as long as they are running on the same machine (regardless
>> of the display location).
>
> A little experimenting shows that starting an extra idl process
> on the same machine, with the same display, does not allocate
> extra licenses. With three idl processes on the machine,
> lmstat -A reports only 10 licenses in use. Starting a
> process on another machine (regardless of display destination)
> requires another 10, but additional processes on that
> machine (with the same display) requires no more licenses).
>
> Stein Vidar
that's what I find (thanks for the lmstat tip). But is this true for
multiprocessor machines as well? If you (happen to) log in on a different
processor for your second session: does this count as different machine?
Just curious,
Martin.
--
------------------------------------------------------------ -------
Dr. Martin Schultz
Department for Engineering&Applied Sciences, Harvard University
109 Pierce Hall, 29 Oxford St., Cambridge, MA-02138, USA
phone: (617)-496-8318
fax : (617)-495-4551
e-mail: mgs@io.harvard.edu
Internet-homepage: http://www-as.harvard.edu/people/staff/mgs/
------------------------------------------------------------ -------
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| Re: IDL with multiple processors [message #13865 is a reply to message #13717] |
Tue, 15 December 1998 00:00 |
mgs
Messages: 144
Registered: March 1995
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Senior Member |
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In article <755cjq$i5e$1@readme.uio.no>, steinhh@ulrik.uio.no (Stein Vidar
Hagfors Haugan) wrote:
> In article <36754DD9.66084666@io.harvard.edu>
> Martin Schultz <mgs@io.harvard.edu> writes:
>
>> Stein Vidar Hagfors Haugan wrote:
>>
>>> A little experimenting shows that starting an extra idl process
>>> on the same machine, with the same display, does not allocate
>>> extra licenses. With three idl processes on the machine,
...
>> that's what I find (thanks for the lmstat tip). But is this true for
>> multiprocessor machines as well? If you (happen to) log in on a different
>> processor for your second session: does this count as different machine?
>
> It appears that multiprocessor machines behave as a single machine.
> At least on an AlphaServer with 4 processors we have here. It seems
> like it's the "hostname" or something similar that's used for ID.
That's different than it was under IDL version 3.x from several years ago.
I was working on a Sun MP/670 with 4 processors at the time. Multiple runs
of IDL each took up to 25% of the total CPU load.
--
Mike Schienle Interactive Visuals, LLC
mgs@ivsoftware.com http://www.ivsoftware.com/
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| Re: IDL with multiple processors [message #13867 is a reply to message #13717] |
Tue, 15 December 1998 00:00 |
pit
Messages: 92
Registered: January 1996
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Member |
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In article <36754DD9.66084666@io.harvard.edu>,
Martin Schultz <mgs@io.harvard.edu> writes:
> that's what I find (thanks for the lmstat tip). But is this true for
> multiprocessor machines as well? If you (happen to) log in on a different
> processor for your second session: does this count as different machine?
No, on most (all?) MP-Machines, a process is not bound to a special
processor. The system kernel does the work to distribute the process on
the available processors, and that can change. So it wouldn't make
sense to lock the session to a specific CPU-ID (AFAIK, now the
hardware-Address of ethernet-cards is used as ID)
Peter
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~
Peter "Pit" Suetterlin http://www.uni-sw.gwdg.de/~pit
Universitaets-Sternwarte Goettingen
Tel.: +49 551 39-5048 pit@uni-sw.gwdg.de
-- * -- * ...-- * -- * ...-- * -- * ...-- * -- * ...-- * -- * ...-- * --
Come and see the stars! http://www.kis.uni-freiburg.de/~ps/SFB
Sternfreunde Breisgau e.V. Tel.: +49 7641 3492
____________________________________________________________ ______________
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| Re: IDL with multiple processors [message #13868 is a reply to message #13717] |
Tue, 15 December 1998 00:00 |
steinhh
Messages: 260
Registered: June 1994
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Senior Member |
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In article <36754DD9.66084666@io.harvard.edu>
Martin Schultz <mgs@io.harvard.edu> writes:
> Stein Vidar Hagfors Haugan wrote:
>
>> A little experimenting shows that starting an extra idl process
>> on the same machine, with the same display, does not allocate
>> extra licenses. With three idl processes on the machine,
>> lmstat -A reports only 10 licenses in use. Starting a
>> process on another machine (regardless of display destination)
>> requires another 10, but additional processes on that
>> machine (with the same display) requires no more licenses).
>>
>> Stein Vidar
>
> that's what I find (thanks for the lmstat tip). But is this true for
> multiprocessor machines as well? If you (happen to) log in on a different
> processor for your second session: does this count as different machine?
It appears that multiprocessor machines behave as a single machine.
At least on an AlphaServer with 4 processors we have here. It seems
like it's the "hostname" or something similar that's used for ID.
Regards,
Stein Vidar
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