Re: [OMPI users] Bad performance when scattering big size of data?

Storm Zhang wrote: Here is what I meant: the results of 500 procs in fact shows it with 272-304(<500) real cores, the program's running time is good, which is almost five times 100 procs' time. So it can be handled very well. Therefore I guess OpenMPI or Rocks OS does make use of

Re: [OMPI users] Bad performance when scattering big size of data?

Here is what I meant: the results of 500 procs in fact shows it with 272-304(<500) real cores, the program's running time is good, which is almost five times 100 procs' time. So it can be handled very well. Therefore I guess OpenMPI or Rocks OS does make use of hyperthreading to do the job. But

[OMPI users] location of ompi libraries

Hi, In Open MPI 1.4.1, the directory lib/openmpi contains about 130 entries, including such things as mca_btl_openib.so. In my build of Open MPI 1.4.2, lib/openmpi contains exactly three items: libompi_dbg_msgq.a libompi_dbg_msgq.la libompi_dbg_msgq.so I have searched my 1.4.2 installation

Re: [OMPI users] Bad performance when scattering big size of data?

On Oct 4, 2010, at 1:48 PM, Storm Zhang wrote: > Thanks a lot, Ralgh. As I said, I also tried to use SGE(also showing 1024 > available for parallel tasks) which only assign 34-38 compute nodes which > only has 272-304 real cores for 500 procs running. The running time is > consistent with 100

Re: [OMPI users] Bad performance when scattering big size of data?

Thanks a lot, Ralgh. As I said, I also tried to use SGE(also showing 1024 available for parallel tasks) which only assign 34-38 compute nodes which only has 272-304 real cores for 500 procs running. The running time is consistent with 100 procs and not a lot fluctuations due to the number of

Re: [OMPI users] mpi_comm_spawn have problems with group communicators

> "Ralph" == Ralph Castain writes: Ralph> On Oct 4, 2010, at 10:36 AM, Milan Hodoscek wrote: >>> "Ralph" == Ralph Castain writes: >> Ralph> I'm not sure why the group communicator would make a Ralph> difference - the code area

Re: [OMPI users] Bad performance when scattering big size of data?

Some of what you are seeing is the natural result of context switchingsome thoughts regarding the results: 1. You didn't bind your procs to cores when running with #procs < #cores, so you're performance in those scenarios will also be less than max. 2. Once the number of procs exceeds the

Re: [OMPI users] Bad performance when scattering big size of data?

Thanks a lot for your reply, Doug. There is one more thing I forgot to mention. For 500 nodes test, I observe if I use SGE, it runs only almost half of our cluster, like 35-38 nodes, not uniformly distributed on the whole cluster but the running time is still good. So I guess it is not a

Re: [OMPI users] Bad performance when scattering big size of data?

In my experience hyperthreading can't really deliver two cores worth of processing simultaneously for processes expecting sole use of a core. Since you really have 512 cores I'm not surprised that you see a performance hit when requesting > 512 compute units. We should really get input from a

Re: [OMPI users] mpi_comm_spawn have problems with group communicators

On Oct 4, 2010, at 10:36 AM, Milan Hodoscek wrote: >> "Ralph" == Ralph Castain writes: > >Ralph> I'm not sure why the group communicator would make a >Ralph> difference - the code area in question knows nothing about >Ralph> the mpi aspects of the job. It

[OMPI users] Bad performance when scattering big size of data?

We have 64 compute nodes which are dual qual-core and hyperthreaded CPUs. So we have 1024 compute units shown in the ROCKS 5.3 system. I'm trying to scatter an array from the master node to the compute nodes using mpiCC and mpirun using C++. Here is my test: The array size is 18KB * Number of

Re: [OMPI users] mpi_comm_spawn have problems with group communicators

> "Ralph" == Ralph Castain writes: Ralph> I'm not sure why the group communicator would make a Ralph> difference - the code area in question knows nothing about Ralph> the mpi aspects of the job. It looks like you are hitting a Ralph> race condition that

Re: [OMPI users] new open mpi user questions

Ed Peddycoart wrote: The machines are RHEL 5.4 machines and an older version of Open MPI was already installed. I understand from the faq that I should not simply over write the old installation, but would it be better if I remove the old version or install the new to a different location. I

Re: [OMPI users] Shared memory

Does OMPI have shared memory capabilities (as it is mentioned in MPI-2)? How can I use them? Andrei On Sat, Sep 25, 2010 at 23:19, Andrei Fokau wrote: > Here are some more details about our problem. We use a dozen of 4-processor > nodes with 8 GB memory on each

[OMPI users] new open mpi user questions

I would like to give Open MPI a test drive on some machines I have in my lab and I have a few questions... The machines are RHEL 5.4 machines and an older version of Open MPI was already installed. I understand from the faq that I should not simply over write the old installation, but would

Re: [OMPI users] Granular locks?

On Oct 1, 2010, at 3:24 PM, Gijsbert Wiesenekker wrote: > I have a large array that is shared between two processes. One process > updates array elements randomly, the other process reads array elements > randomly. Most of the time these writes and reads do not overlap. > The current version of

Re: [OMPI users] mpi_comm_spawn have problems with group communicators

I'm not sure why the group communicator would make a difference - the code area in question knows nothing about the mpi aspects of the job. It looks like you are hitting a race condition that causes a particular internal recv to not exist when we subsequently try to cancel it, which generates

Re: [OMPI users] Error when using OpenMPI with SGE multiple hosts

It looks to me like your remote nodes aren't finding the orted executable. I suspect the problem is that you need to forward the path and ld_library_path tot he remove nodes. Use the mpirun -x option to do so. On Oct 4, 2010, at 5:08 AM, Chris Jewell wrote: > Hi all, > > Firstly, hello to

[OMPI users] Error when using OpenMPI with SGE multiple hosts

Hi all, Firstly, hello to the mailing list for the first time! Secondly, sorry for the non-descript subject line, but I couldn't really think how to be more specific! Anyway, I am currently having a problem getting OpenMPI to work within my installation of SGE 6.2u5. I compiled OpenMPI