| Re: IDL on Dual processor Linux SMP box? [message #11886] |
Thu, 04 June 1998 00:00 |
steinhh
Messages: 260
Registered: June 1994
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Senior Member |
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I think the licence policy is "one licence per screen and
user". A single user working on a single screen should thus
only occupy a single licence, even with several IDL processes.
Two users on a single screen (crowded office :-) might occupy
two licences, and a single user on two screens would occupy
two licences, AFAIK.
As for the benefits of multiple processors, I sometimes
run IDL in Remote Procedure Call (RPC) server mode to use
it as a "plotting engine" for my C programs. This would
(at least in theory) allow your C program to go on with
it's business (on one processor) while IDL is plotting the
results you just sent. The problem is though, that the RPC
call probably waits for the plotting command to finish
successfully...? Maybe it's possible to set the timeout
to 0 seconds, but... It would be nice to be able to do
RPC calls concurrently in some cleaner way.
Regards,
Stein Vidar
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| Re: IDL on Dual processor Linux SMP box? [message #11895 is a reply to message #11886] |
Wed, 03 June 1998 00:00  |
J.D. Smith
Messages: 214
Registered: August 1996
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Senior Member |
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John Krist wrote:
>
> Greetings:
>
> I have been considering getting a dual processor Pentium II workstation
> on which I would run Linux in SMP mode, mostly to use IDL. Does anyone
> have any experience with such a configuration? I recall somewhere that
> an IDL license on a x86 Linux box is tied to the Ethernet card address,
> rather than the processor serial number (which perhaps Intel processors do
> not report). If so, I could run IDL on both processors at the same time
> under the same license, correct?
>
> The system I may get is a Dell Precision Workstation 410 with dual
> 400 MHz processors, with the SCSI and video cards replaced with Buslogic
> SCSI and Matrox Millenium II video cards for better Linux compatibility
> (I can only get boxes from big-name companies, not from small-name Linux
> specialists).
>
> Thanks,
> John Krist
> krist@stsci.edu
>
It's not clear to me how some parts of the licensing works, but I can certainly run
two cuncurrent IDL's as a single user on my 1-license, 1-processor, Linux machine.
Here is an excerpt of one of my postings concering the IDL speed survey, IDLSPEC, on
a dual-processor linux machine, in which just this scenario is described:
> The multi-processor machines suffered, since IDL is not multi-threaded
> on any architecture I know of. However, Joe Harrington, a local Linux
> guru and builder of multi-processor Pentium boxes, did demonstrate the
> superior capability of his dual Pentium-II machine to me by running
> concurrently two sessions of IDL each running time_test2. As he
> expected, both sets of tests ran in parallel about 1.75 times as fast as
> when run one at a time. However, since this is not a normal mode of
> operating IDL, I entered only his single-session results.
It's not clear to me how one would use two separate IDL processes effectively, but
keep in mind that other processes (X server, etc.) would be split across both
processors. The additional-performance-to-cost ratio for single IDL processes may
not be compelling, though. There are several old posts in the archives discussing
this subject.
JD
--
J.D. Smith |*| WORK: (607) 255-5842
Cornell University Dept. of Astronomy |*| (607) 255-4083
206 Space Sciences Bldg. |*| FAX: (607) 255-5875
Ithaca, NY 14853 |*|
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