Hi Joe, Thanks for the details, it is always good to have feedback from users (your anecdote is actually very good!). About the Intel compiler, i know that OSCAR developers had in the past discussions with Intel about the possibility to create an OSCAR package for it, but it was before i became active in the project and therefore i do not really know if they come up with a plan (DongInn, do you remember something about that?). But now that the OSCAR status is much more clear for me, i can imagine to work on that issue at some points, especially since i am interested in using more the Intel compiler.
Selon "Greenseid, Joseph M." <[EMAIL PROTECTED]>: > Hi Geoffroy, > > To answer your question, yes, many of my users do some use some specific > compiler options beyond the defaults for optimization. I have a counterpart > in my group here who is extremely strong on the applications side, and he > works with our users to optimize the performance of their code -- his usual > first step is to try to optimize the compile to see how much performance he > can get out of it before going back to muck with the application itself. > > I don't think we here have any numbers on performance gain of Intel over GCC; > most of our users have a history of using the Intel compiler because at some > point in the past, it was (much?) better than GCC for them. I can give one > anecdote, which may be more amusing than useful. We had a user who had a > bioinformatics type code that was built in Python with C extensions. When my > friend went to help him try to get some better performance, he wanted to > recompile with the Intel compiler instead of GCC. However, Python will use > the compiler that it was built with, so he had to build Python from source > with the Intel compiler before he could get it to use the Intel compiler for > the extensions. After all that, it did run twice as fast with nothing more > than the SSE enabled Intel compiler. As a data point, it's not real helpful, > but it was a good speed-up, after a crazy amount of effort. :) > > I haven't been following GCC very much, since everyone we work with just > likes to use the Intel compiler. I'll have to go check out their > auto-vectorization plans to see what's up. Thanks for that tip, btw. > > I agree that Intel licensing is a problem. Unfortunately, not all users are > going to be non-commercial, so assuming that and hacking in the > download/inclusion of the free non-commercial version might not be the safest > idea. I honestly don't know how to get around this in a generic case beyond > the possibility of doing the 30 day evaluation version and forcing the user > to go out and get a long term license on their own afterwards. All the > licensing stuff gets very sticky. > > I agree that a better first step might be figuring out how to offer Intel > compilers/tools, rather than offering Intel optimized packages. If OSCAR can > figure out how to integrate offering Intel tools (compilers, libs like CMKL, > tools MPI, etc?), then offering tools built with the Intel offerings (OFED) > would likely be a lot easier. > > --Joe > > ________________________________ > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Sent: Wed 3/26/2008 10:13 AM > To: [email protected]; Greenseid, Joseph M. > Subject: Re: [Oscar-devel] OFED > > > > Hi Joe, > > Thanks for the details, it is actually very interesting to have some return > of > experience. However, my question was actually very unclear (my bad), I was > actually looking for more details about the performance gain (10% in average > for > MPI applications?). > I also know that if you start to play with the compiling options you can > improve > the global performance of your app (both with gcc and the Intel compiler). I > am > just curious, are your users only using the default compiling options? or do > they try to tune the compiling procedure for each compiler? > I also wonder if the latest version of GCC will improve performance compared > to > the Intel compiler; it is supposed to include some auto-vectorization > mechanism). But that's another story, i digress here. :-) > > On the OSCAR side, the problem with the Intel compiler is the license: we > cannot > install automatically the Intel compiler without asking the user to agree > with > Intel licensing stuff, and clearly, currently the only solution to do so is > via > a hack (we do not have a well-defined method for that). > To summarize, my concern is the following: why should we ship OFED compiled > with > the Intel compiler if you do not have a good support of the Intel compiler by > default. My feeling is the usage of the Intel compiler will really be a plus > if > we can also compile the application. In other term, it seems to me that > instead > of working on a OFED OPKG compiled with the Intel compiler we should be > better > off working on a OPKG for the Intel compiler. > Do you agree with that? > > > Selon "Greenseid, Joseph M." <[EMAIL PROTECTED]>: > > > My users find that using the Intel compilers do increase application > > performance for them over GCC (especially with x86_64 architecture, because > > of the auto-vectorization you can get with the SSE aware compilers). > > > > Given the choice, none of the folks using my system choose GCC over Intel > > (currently, all my users use Intel compilers and Intel flavors of MPI, even > > though GCC is also available). > > > > I would say that the ability to use the Intel compilers with MPI would be > > valuable, if OFED is would be considered in OSCAR. If Intel flavors aren't > > included, I would probably have to choose to not install it via OSCAR, but > > instead do it myself by hand to get them. > > > > Just the thoughts of one user... > > > > --Joe > > > > ________________________________ > > > > From: [EMAIL PROTECTED] on behalf of > > [EMAIL PROTECTED] > > Sent: Tue 3/25/2008 12:03 AM > > To: [email protected]; Paul Greidanus > > Subject: Re: [Oscar-devel] OFED > > > > > > > > Hi, > > > > Just another idea: instead of focusing on the support of multiple compiler > > (does > > it really improve the global performance for all applications?), why not > > working > > on the virtualization stuff that are today included in OFED (Panda team > work > > typically), i.e., VMM-bypass and efficient VM migration? > > > > That's should be fun to do and it fits perfectly the OSCAR-V extension > > (which, i > > hope, will be very soon integrated directly into OSCAR). > > > > My 2 cents, > > > > Selon Paul Greidanus <[EMAIL PROTECTED]>: > > > > > Hi All, > > > > > > I was just looking and thinking about OFED, and how to package it into > > > OSCAR, and I'm thinking it might be possible to just copy the SRPMS in, > > > and have the oscar build scripts build the RPMS, like the rest of > > > oscar? Also, we could use an Intel/pgi compiler to build the RPMS > > > pretty easily as well, and have the option of installing optimized > > > libraries, rather then just GCC.. > > > > > > Or do I not know what I'm talking about.. > > > > > > Paul > > > > > > ------------------------------------------------------------------------- > > > This SF.net email is sponsored by: Microsoft > > > Defy all challenges. Microsoft(R) Visual Studio 2008. > > > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > > > _______________________________________________ > > > Oscar-devel mailing list > > > [email protected] > > > https://lists.sourceforge.net/lists/listinfo/oscar-devel > > > > > > > > > > > ------------------------------------------------------------------------- > > This SF.net email is sponsored by: Microsoft > > Defy all challenges. Microsoft(R) Visual Studio 2008. > > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > > _______________________________________________ > > Oscar-devel mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/oscar-devel > > > > > > > > > > > ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ Oscar-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/oscar-devel
