Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] Buffer size limit and memory consumption problem on heterogeneous (32 bit / 64 bit) machines
From: Olivier Riff (oliriff_at_[hidden])
Date: 2010-05-20 07:28:33


2010/5/20 Nysal Jan <jnysal_at_[hidden]>

> This probably got fixed in https://svn.open-mpi.org/trac/ompi/ticket/2386
> Can you try 1.4.2, the fix should be in there.
>
>

I will test it soon (takes some time to install the new version on each
node) . It would be perfect if it fixes it.
I will tell you the result asap.

Thanks.

Olivier

> Regards
> --Nysal
>
>
> On Thu, May 20, 2010 at 2:02 PM, Olivier Riff <oliriff_at_[hidden]>wrote:
>
>> Hello,
>>
>> I assume this question has been already discussed many times, but I can
>> not find on Internet a solution to my problem.
>> It is about buffer size limit of MPI_Send and MPI_Recv with heterogeneous
>> system (32 bit laptop / 64 bit cluster).
>> My configuration is :
>> open mpi 1.4, configured with: --without-openib --enable-heterogeneous
>> --enable-mpi-threads
>> Program is launched a laptop (32 bit Mandriva 2008) which distributes
>> tasks to do to a cluster of 70 processors (64 bit RedHat Entreprise
>> distribution):
>> I have to send various buffer size from few bytes till 30Mo.
>>
>> I tested following commands:
>> 1) mpirun -v -machinefile machinefile.txt MyMPIProgram
>> -> crash on client side ( 64 bit RedHat Entreprise ) when sent buffer size
>> > 65536.
>> 2) mpirun --mca btl_tcp_eager_limit 30000000 -v -machinefile
>> machinefile.txt MyMPIProgram
>> -> works but has the effect of generating gigantic memory consumption on
>> 32 bit machine side after MPI_Recv. Memory consumption goes from 800Mo to
>> 2,1Go after receiving about 20ko from each 70 clients ( a total of about 1.4
>> Mo ). This makes my program crash later because I have no more memory to
>> allocate new structures. I read in a openmpi forum thread that setting
>> btl_tcp_eager_limit to a huge value explains this huge memory consumption
>> when a message sent does not have a preposted ready recv. Also after all
>> messages have been received and there is no more traffic activity : the
>> memory consumed remains at 2.1go... and I do not understand why.
>>
>> What is the best way to do in order to have a working program which also
>> has a small memory consumption (the speed performance can be lower) ?
>> I tried to play with mca paramters btl_tcp_sndbuf and mca btl_tcp_rcvbuf,
>> but without success.
>>
>> Thanks in advance for you help.
>>
>> Best regards,
>>
>> Olivier
>>
>> _______________________________________________
>> users mailing list
>> users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>
>
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>