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Hadoop, mail # dev - Hadoop + MPI


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Re: Hadoop + MPI
Ralph Castain 2011-11-22, 00:35

On Nov 21, 2011, at 5:04 PM, <[EMAIL PROTECTED]> wrote:

> Ralph,
>
> Yes, I have completed the first step, although I would really like that
> code to be part of the MPI Application Master (Chris Douglas suggested a
> way to do this at ApacheCon).
>
> Regarding the remaining steps, I have been following discussions on the
> open mpi mailing lists, and reading code for hwloc.
>
> If you are making a trip to Cisco HQ sometime soon, I would like to have a
> face-to-face about hwloc.

Not sure that looks likely right now - my project at Cisco is done, and it appears I'll be leaving the company soon.

> I have so far avoided to use a native task
> controller for spawning MPI jobs, but given the lack of support for
> binding in Java, it looks like I will have to bite the bullet.

I was actually looking at porting the binding support to Java as it looks feasible to do so, and I can understand not wanting to absorb all that configuration code to handle it in C. Given the loss of job, I have some free time on my hands while I search for employment, so I thought I might spend it looking at the Hadoop integration - since you have completed the wireup, I might look at this next.

>
> - milind
>
> ---
> Milind Bhandarkar
> Greenplum Labs, EMC
> (Disclaimer: Opinions expressed in this email are those of the author, and
> do not necessarily represent the views of any organization, past or
> present, the author might be affiliated with.)
>
>
>
> On 11/21/11 3:54 PM, "Ralph Castain" <[EMAIL PROTECTED]> wrote:
>
>> Hi Milind
>>
>> Glad to hear of the progress - I recall our earlier conversation. I
>> gather you have completed step 1 (wireup) - have you given any thought to
>> the other two steps? Anything I can do to help?
>>
>> Ralph
>>
>>
>> On Nov 21, 2011, at 4:47 PM, <[EMAIL PROTECTED]> wrote:
>>
>>> Hi Ralph,
>>>
>>> I spoke with Jeff Squyres  at SC11, and updated him on the status of my
>>> OpenMPI port on Hadoop Yarn.
>>>
>>> To update everyone, I have OpenMPI examples running on #Yarn, although
>>> it
>>> requires some code cleanup and refactoring, however that can be done as
>>> a
>>> later step.
>>>
>>> Currently, the MPI processes come up, get submitting client's IP and
>>> port
>>> via environment variables, connect to it, and do a barrier. The result
>>> of
>>> this barrier is that everyone in MPI_COMM_WORLD gets each other's
>>> endpoints.
>>>
>>> I am aiming to submit the patch to hadoop by the end of this month.
>>>
>>> I will publish the openmpi patch to github.
>>>
>>> (As I mentioned to Jeff, OpenMPI requires a CCLA for accepting
>>> submissions. That will take some time.)
>>>
>>> - Milind
>>>
>>> ---
>>> Milind Bhandarkar
>>> Greenplum Labs, EMC
>>> (Disclaimer: Opinions expressed in this email are those of the author,
>>> and
>>> do not necessarily represent the views of any organization, past or
>>> present, the author might be affiliated with.)
>>>
>>>
>>>
>>>>
>>>> I'm willing to do the integration work, but wanted to check first to
>>>> see
>>>> if (a) someone in the Hadoop community is already doing so, and (b) if
>>>> you would be interested in seeing such a capability and willing to
>>>> accept
>>>> the code contribution?
>>>>
>>>> Establishing MPI support requires the following steps:
>>>>
>>>> 1. wireup support. MPI processes need to exchange endpoint info (e.g.,
>>>> for TCP connections, IP address and port) so that each process knows
>>>> how
>>>> to connect to any other process in the application. This is typically
>>>> done in a collective "modex" operation. There are several ways of doing
>>>> it - if we proceed, I will outline those in a separate email to solicit
>>>> your input on the most desirable approach to use.
>>>>
>>>> 2. binding support. One can achieve significant performance
>>>> improvements
>>>> by binding processes to specific cores, sockets, and/or NUMA regions
>>>> (regardless of using MPI or not, but certainly important for MPI
>>>> applications). This requires not only the binding code, but some logic