Re: IB fabrics

From: Chris Harrison (charris5_at_gmail.com)
Date: Fri Jan 06 2012 - 12:52:21 CST

Dear Brian,

When you say it "doesn't do it very well then," could you elaborate?
Are crashes more frequent, and if so are they reproducible and what is
the error message? Or is a difference in performance speed compared to
mellanox?

We'd appreciate anything more quantitative you could send our way on the
difference.

Best,
Chris

--
Chris Harrison, Ph.D.
Theoretical and Computational Biophysics Group
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave., Urbana, IL 61801
char_at_ks.uiuc.edu                          Voice: 773-570-0329 
http://www.ks.uiuc.edu/~char              Fax:   217-244-6078
"Bennion, Brian" <Bennion1_at_llnl.gov> writes:
> Date: Fri, 6 Jan 2012 10:39:04 -0800
> From: "Bennion, Brian" <Bennion1_at_llnl.gov>
> To: Thomas Bishop <bishop_at_latech.edu>
> CC: "namd-l_at_ks.uiuc.edu" <namd-l_at_ks.uiuc.edu>
> Subject: RE: namd-l: IB fabrics
> 
> The only concern that I have seen is the implementation of charm++ on the two IB layers when using IBVERBS instead of  the mpi versions.
> 
> at our institution we have qlogic and mellanox ib hardware.  qlogic in our implementation will only run ibverbs in a software mode and it doesn't do it very well even then.
> 
> Brian
> 
> 
> 
> ________________________________________
> From: owner-namd-l_at_ks.uiuc.edu [owner-namd-l_at_ks.uiuc.edu] On Behalf Of Axel Kohlmeyer [akohlmey_at_gmail.com]
> Sent: Friday, January 06, 2012 9:58 AM
> To: Thomas Bishop
> Cc: namd-l_at_ks.uiuc.edu
> Subject: Re: namd-l: IB fabrics
> 
> On Fri, Jan 6, 2012 at 12:42 PM, Thomas Bishop <bishop_at_latech.edu> wrote:
> > Is namd very sensitive to which vendor is used for a 40Gbps IB fabric.
> > Specifically I'm interested in Qlogic vs. Mellanox.
> 
> don't think so, why should it be?
> 
> i can think of at least 10 other things that
> i would worry about more before worrying
> about ib vendor impact on NAMD speed.
> 
> . and the things w.r.t. IB vendors that i *would*
> worry about are independent of the application.
> 
> cheers,
>     axel.
> 
> > Any comments greatly appreciated.
> > Thanks
> > TOm
> >
> >
> > --
> > *******************************
> >   Thomas C. Bishop
> >    Tel: 318-257-5209
> >    Fax: 318-257-3823
> > http://dna.engr.latech.edu
> > ********************************
> >
> 
> 
> 
> --
> Dr. Axel Kohlmeyer
> akohlmey_at_gmail.com  http://goo.gl/1wk0
> 
> College of Science and Technology
> Temple University, Philadelphia PA, USA.
> 
> 

This archive was generated by hypermail 2.1.6 : Wed Feb 29 2012 - 05:24:38 CST