Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: Re: [OMPI devel] How to add a schedule algorithm to the pml
From: Rainer Keller (keller_at_[hidden])
Date: 2010-09-27 05:37:34


Kenneth,
please note, that the slides of the conference's program have been uploaded to
  http://www.eurompi2010.org/program/

Best regards,
Rainer

On Wednesday 22 September 2010 17:53:12 Kenneth Lloyd wrote:
> Jeff,
>
> Is that EuroMPI2010 ob1 paper publicly available? I get involved in various
> NUMA partitioning/architecting studies and it seems there is not a lot of
> discussion in this area.
>
> Ken Lloyd
>
> ==================
> Kenneth A. Lloyd
> Watt Systems Technologies Inc.
>
>
>
> -----Original Message-----
> From: devel-bounces_at_[hidden] [mailto:devel-bounces_at_[hidden]] On
> Behalf Of Jeff Squyres Sent: Wednesday, September 22, 2010 6:00 AM
> To: Open MPI Developers
> Subject: Re: [OMPI devel] How to add a schedule algorithm to the pml
>
> Sorry for the delay in replying -- I was in Europe for the past two weeks;
> travel always makes me waaaay behind on my INBOX...
>
> On Sep 14, 2010, at 9:56 PM, 张晶 wrote:
> > I tried to add a schedule algorithm to the pml component ,ob1 etc. Poorly
> > I can only find a paper named "Open MPI: A Flexible High Performance
> > MPI" and some annotation in the source file. From them , I know ob1 has
> > implemented round-robin& weighted distribution algorithm. But after
> > tracking the MPI_Send(),I cann't figure out the location of these
> > implement ,let alone to add a new schedule algorithm. I have two
> > questions :
> > 1.The location of the schedule algorithm ?
>
> It's complicated -- I'd say that the PML is probably among the most
> complicated sections of Open MPI because it is the main "engine" that
> enforces the MPI point-to-point semantics. The algorithm is fairly well
> distribute throughout the PML source code. :-\
>
> > 2.There are five components :cm,crcpw ,csum ,ob1,V in the pml framework .
> > The function of these components?
>
> cm: this component drives the MTL point-to-point components. It is mainly
> a thin wrapper for network transports that provide their own MPI-like
> matching semantics. Hence, most of the MPI semantics are effectively done
> in the lower layer (i.e., in the MTL components and their dependent
> libraries). You probably won't be able to do much here, because such
> transports (MX, Portals, etc.) do most of their semantics in the network
> layer -- not in Open MPI. If you have a matching network layer, this is
> the PML that you probably use (MX, Portals, PSM).
>
> crcpw: this is a fork of the ob1 PML; it add some failover semantics.
>
> csum: this is also a fork of the ob1 PML; it adds checksumming semantics
> (so you can tell if the underlying transport had an error).
>
> v: this PML uses logging and replay to effect some level of fault
> tolerance. It's a distant fork of the ob1 PML, but has quite a few
> significant differences.
>
> ob1: this is the "main" PML that most users use (TCP, shared memory,
> OpenFabrics, etc.). It gangs together one or more BTLs to send/receive
> messages across individual network transports. Hence, it supports true
> multi-device/multi-rail algorithms. The BML (BTL multiplexing layer) is a
> thin management later that marshals all the BTLs in the process together
> -- it's mainly array handling, etc. The ob1 PML is the one that decides
> multi-rail/device splitting, etc. The INRIA folks just published a paper
> last week at Euro MPI about adjusting the ob1 scheduling algorithm to also
> take NUMA/NUNA/NUIOA effects into account, not just raw bandwidth
> calculations.
>
> Hope this helps!

-- 
----------------------------------------------------------------
 Dr.-Ing. Rainer Keller  http://www.hlrs.de/people/keller
 HLRS                         Tel: ++49 (0)711-685 6 5858
 Nobelstrasse 19                 Fax: ++49 (0)711-685 6 5832
 70550 Stuttgart                    email: keller_at_[hidden]     
 Germany                             AIM/Skype:rusraink