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Subject: Re: [OMPI users] Myrinet optimization with OMP1.3 and macosX
From: Ricardo Fernández-Perea (rfernandezperea_at_[hidden])
Date: 2009-05-04 10:54:42


I finally have opportunity to run the imb-3.2 benchmark over myrinet I am
running in a cluster of 16 node Xservers connected with myrinet 15 of them
are 8core ones and the last one is a 4 cores one. Having a limit of 124
process
I have run the test with the bynode option so from the 2 to the 16 process
test is always running 1 process by node.

the following test pingpong, pingping, sendrecv, exchange presents a strong
drop in performance with the 64k packet size.

any idea where I should look for the cause.

Ricardo

On Fri, Mar 20, 2009 at 7:32 PM, Ricardo Fernández-Perea <
rfernandezperea_at_[hidden]> wrote:

> It is the F-2M but I think for inter-node communication should be
> equivalents.
> I have not run and MPI pingpong benchmark yet.
>
> The truth is I have a 10 days travel coming next week and I thought I can
> take some optimization "light reading" with me.
>
> so I know what I must look for when I came back.
>
> Ricardo
>
>
> On Fri, Mar 20, 2009 at 5:10 PM, Scott Atchley <atchley_at_[hidden]> wrote:
>
>> On Mar 20, 2009, at 11:33 AM, Ricardo Fernández-Perea wrote:
>>
>> This are the results initially
>>> Running 1000 iterations.
>>> Length Latency(us) Bandwidth(MB/s)
>>> 0 2.738 0.000
>>> 1 2.718 0.368
>>> 2 2.707 0.739
>>> <snip>
>>> 1048576 4392.217 238.735
>>> 2097152 8705.028 240.913
>>> 4194304 17359.166 241.619
>>>
>>> with export MX_RCACHE=1
>>>
>>> Running 1000 iterations.
>>> Length Latency(us) Bandwidth(MB/s)
>>> 0 2.731 0.000
>>> 1 2.705 0.370
>>> 2 2.719 0.736
>>> <snip>
>>> 1048576 4265.846 245.807
>>> 2097152 8491.122 246.982
>>> 4194304 16953.997 247.393
>>>
>>
>> Ricardo,
>>
>> I am assuming that these are PCI-X NICs. Given the latency and bandwidth,
>> are these "D" model NICs (see the top of the mx_info output)? If so, that
>> looks about as good as you can expect.
>>
>> Have you run Intel MPI Benchmark (IMB) or another MPI pingpong type
>> benchmark?
>>
>> Scott
>>
>> _______________________________________________
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>
>