use multiple cores

Asked by Rune Philosof on 2009-07-10

Isn't lapack supposed to be able to use multiple cores?
It does not on my computer.
How do I enable that?

I use the program R a lot. This program uses lapack for its matrix calculations, and I need it to use all my cores for these operations.

Besides, when I run:
/usr/lib/liblapack3gf/xlintimz < /usr/share/doc/liblapack-test/examples/zband.in
I see that only one processor is used.

Question information

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Ubuntu lapack Edit question
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Last query:
2009-07-12
Last reply:
2009-07-14

The system makes use of the multiple cores because processes run separately so programs dont control how many cores are being used. The scheduler does all of the work in this area. If your having performance issues go into the system monitor and give the program a high priority.

Hope that helps
Shane

The system makes use of the multiple cores because processes run separately so programs dont control how many cores are being used. The scheduler does all of the work in this area. If your having performance issues go into the system monitor and give the program a high priority.

Hope that helps
Shane

Rune Philosof (olberd) said : #3

Incorrect. Programs (and libraries in this case) can start multiple threads to utilize multiple cores.

From http://www.netlib.org/lapack/:
The original goal of the LAPACK project was to make the widely used EISPACK and LINPACK libraries run efficiently on shared-memory vector and parallel processors.

So LAPACK is specifically designed to be able to use my multiple cores. It just isn't enabled it seems.
Or at least that is my question.

Tom (tom6) said : #4

Hmmm, i'm not sure what is going on here but i installed "conky" and reconfigured the script to show me % usage of each core in a time-graph and see that most of my normal usage is split between both cores - usually about 20% of one core and maybe about 50-60% of the other. When i start pushing my machine a bit more it sometimes builds up to 40-50% on one core with still about 50-60% in the other - i haven't yet been able to find an excuse to push my machine beyond that because by the time i have about 50% on both cores i already have all my heaviest apps open and running. I'm thinking about installing a Windows game at some point but haven't got around to it yet.

So i really suggest trying to use install and adapt "conky" to dynamically monitor what % usage you get from each core in what it calls a "bar chart" <sighs> <shakes head> - still although the name is probably american it does seem to do very much the right job.

In the meantime thanks for giving us a link to the website of the program you are talking about. I'm just about to start reading that now in case i spot something obvious but i have no experience with fortran so doubt i'll be much use understanding that.

Anyway, hopefully between us all we'll spot something and work out what mis-communication is going on & where.
Thanks, good luck and regards from
Tom :)

Tom (tom6) said : #5

I thought it might have something to do with trying to run a windows program under linux but while there are extensive notes on installing to Windows machines there are also instructions to install to Unix platforms
http://www.netlib.org/lapack/lawn41/node10.html
although these seem somewhat sparse and i wonder if there needs to be a few more things done to run this on linux, specifically ubuntu, rather than a generalised unix system. Linux is based on unix but there may be some slight differences. I just don't know enough to know whether there are issues around that.

Good luck and regards from
Tom :)

Tom (tom6) said : #6

i did find a way to contact them directly to ask for some help because i think i'm looking in the wrong place

<email address hidden>

i hope you find this useful in getting help directly from them but i would really like to direct them to this thread. Would that be ok?
Regards from
Tom :)

Tom (tom6) said : #7

Ok, i have had this reply from them about lapack

"
Tom,
The LAPACK installation guide is here:
http://www.netlib.org/lapack/lawn81/index.html
If you give me the compilers and the BLAS library you are planning to use, I can help you for the configuration of the make.inc
Otherwise Ubuntu has a LAPACK library available
http://packages.ubuntu.com/hu/source/hardy/lapack
but it is not the latest version.
Regards
Julie
"

I hope this helps!
Good luck and reagrds from
Tom :)

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