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From: George Bosilca (bosilca_at_[hidden])
Date: 2006-06-13 11:46:48


On Jun 13, 2006, at 11:07 AM, Brock Palen wrote:

> Here are the results with -mca mpi_leave_pinned
> The results are as expected, they are exactly similar to the mpich
> results. Thank you for the help. I have attached a plot with all
> three and the raw data for anyones viewing pleasure.

We never doubt about that :)

>
> Im still curious about does mpi_leave_pinned affect real jobs if
> its not included? for the most part for large messages of the size
> used in this test will never be seen. So the effect should be
> negligible? Clarification?
> Note I am a admin not a MPI programmer have very lax experience
> with real code.

If you want/can run some real applications with and without this flag
and compare them it will be more than useful. We never went deeper
than some benchmarks on this topic. Additional information is
welcome ...

   Thanks,
     george.

> <bwmyirnet.png>
> <bwMCA.o1985>
> <bwMPICH.o1978>
> <bwOMPI.o1979>
>
> Brock Palen
> Center for Advanced Computing
> brockp_at_[hidden]
> (734)936-1985
>
>
> On Jun 13, 2006, at 10:38 AM, Brock Palen wrote:
>
>> Ill provide new numbers soon with the --mac mpi_leave_pinned 1
>> I'm currious how does this affect real application performace? This
>> ofcourse is a synthetic test using NetPipe. For regular apps that
>> move decent amounts of data but want low latency more.
>> Will that be affected?
>>
>> Brock Palen
>> Center for Advanced Computing
>> brockp_at_[hidden]
>> (734)936-1985
>>
>>
>> On Jun 13, 2006, at 10:26 AM, George Bosilca wrote:
>>
>>> Unlike mpich-gm, Open MPI does not keep the memory pinned by
>>> default.
>>> You can force this by ading the "--mca mpi_leave_pinned 1" to your
>>> mpirun command or by adding it into the Open MPI configuration file
>>> as specified on the FAQ (section performance). I think that
>>> should be
>>> the main reason what you're seeing a such degradation of
>>> performances.
>>>
>>> If this does not solve your problem, can you please provide the new
>>> performance as well as the output of the command "ompi_info --param
>>> all all".
>>>
>>> Thanks,
>>> george.
>>>
>>> On Jun 13, 2006, at 10:01 AM, Brock Palen wrote:
>>>
>>>> I ran a test using openmpi-1.0.2 on OSX vs mpich-1.2.6 from
>>>> mryicom and i get lacking results from OMPI,
>>>> at point point there is a small drop in bandwidth for both MPI
>>>> libs, but open mpi does not recover like mpich, and further on you
>>>> see a decreese in bandwidth for OMPI on gm.
>>>>
>>>> I have attached in png and the outputs from the test (there are
>>>> two for OMPI )
>>>> <bwMyrinet.png>
>>>> <bwOMPI.o1969>
>>>> <bwOMPI.o1979>
>>>> <bwMPICH.o1978>
>>>>
>>>> Brock Palen
>>>> Center for Advanced Computing
>>>> brockp_at_[hidden]
>>>> (734)936-1985
>>>>
>>>>
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>>
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