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Subject: Re: [OMPI users] Fwd: Open MPI v1.4 cant find default hostfile
From: Ralph Castain (rhc_at_[hidden])
Date: 2010-04-17 15:13:47


On Apr 17, 2010, at 11:17 AM, Mario Ogrizek wrote:

> Hahaha, ok then that WAS silly! :D
> So there is no way to utilize both cores with mpi?

We are using both cores - it is just that they are on the same node. Unless told otherwise, the processes will use shared memory for communication.

>
> Ah well, I'll correct that.
>
> From console, im starting a job like this: mpirun -np 4 Program, where i want to run a Program on 4 processors.
> I was just stumbled when i got same output 4 times, like there are 4 processes ranked 0.
> While with the old version of mpi (1.2) same execution would give 4 processes ranked 0..3.

And so you should - if not, then there is something wrong. No way mpirun would start 4 processes ranked 0. How are you printing the rank? Are you sure you are getting it correctly?

>
> Hope you see my question.
>
> On Sat, Apr 17, 2010 at 6:29 PM, Ralph Castain <rhc_at_[hidden]> wrote:
>
> On Apr 17, 2010, at 1:16 AM, Mario Ogrizek wrote:
>
>> I am new to mpi, so I'm sorry for any silly questions.
>>
>> My idea was to try to use dual core machine as two nodes. I have a limited access to a cluster, so this was just for "testing" purposes.
>> My default hostfile contains usual comments and this two nodes:
>>
>>> node0
>>> node1
>> I thought that each processor is a node for MPI purpose.
>
> I'm afraid not - it is just another processor on that node. So you only have one node as far as OMPI is concerned.
>
>> Im not sure what do you mean with "mpirun cmd line"?
>
> How are you starting your job? The usual way is with "mpirun -n N ...". That is what we mean by the "mpirun cmd line" - i.e., what command are you using to start your job?
>
> It sounds like things are actually working correctly. You might look at "mpirun -h" for possible options of interest.
>
>
>>
>> Regards,
>>
>> Mario
>>
>> On Sat, Apr 17, 2010 at 1:54 AM, Ralph Castain <rhc_at_[hidden]> wrote:
>>
>> On Apr 16, 2010, at 5:08 PM, Mario Ogrizek wrote:
>>
>>> I checked the default MCA param file, and found it was there that was (automatically) specified as a relative path, so i changed it.
>>> So now, it works, altho, still something is not right.
>>> Seems like its creating 4 times only 1 process.
>>> Not sure if it has to do something with my hostfile, it contains:
>>>
>>> node0
>>> node1
>>>
>>> I am running this on a simple dualcore machine, so i specified it as a localhost with two nodes.
>>
>> I don't understand this comment - a dual core machine would still be a single node. Just happens to have two processors in it.
>>
>> Could you send the contents of your hostfile and your mpirun cmd line?
>>
>>>
>>> Regards,
>>>
>>> Mario
>>>
>>> On Sat, Apr 17, 2010 at 12:52 AM, Mario Ogrizek <mario.guardian_at_[hidden]> wrote:
>>> I understand, so, its looking for a working_dir/usr/local/etc/openmpi-default-hostfile
>>> I managed to run a hello world program from the console, while my wd was just "/" and it worked, altho strangely...
>>> example for 4 procs:
>>>
>>> Hello MPI World From process 0: Num processes: 1
>>> Hello MPI World From process 0: Num processes: 1
>>> Hello MPI World From process 0: Num processes: 1
>>> Hello MPI World From process 0: Num processes: 1
>>>
>>> So, you are saying i allways have to be in "/" to run mpi programs, or there is a way for mpi to search absolute path?
>>> It seems pretty inconvinient this way.
>>> I think v 1.2 didnt have this limitation.
>>>
>>> Does this have to do anything with LD_LIBRARY_PATH?
>>>
>>> Regards,
>>>
>>> Mario
>>>
>>> On Fri, Apr 16, 2010 at 7:46 PM, Ralph Castain <rhc_at_[hidden]> wrote:
>>> How did you specify it? Command line? Default MCA param file?
>>>
>>> On Apr 16, 2010, at 11:44 AM, Mario Ogrizek wrote:
>>>
>>>> Any idea how to solve this?
>>>>
>>>> On Fri, Apr 16, 2010 at 7:40 PM, Timur Magomedov <timur.magomedov_at_[hidden]> wrote:
>>>> Hello.
>>>> It looks that you hostfile path should
>>>> be /usr/local/etc/openmpi-default-hostfile not
>>>> usr/local/etc/openmpi-default-hostfile but somehow Open MPI gets the
>>>> second path.
>>>>
>>>> В Птн, 16/04/2010 в 19:10 +0200, Mario Ogrizek пишет:
>>>> > Well, im not sure why should i name it /openmpi-default-hostfile
>>>> > Especially, because mpirun v1.2 executes without any errors.
>>>> > But, i made a copy named /openmpi-default-hostfile, and still, the
>>>> > same result.
>>>> >
>>>> > This is the whole error message for a simple hello world program:
>>>> >
>>>> >
>>>> > Open RTE was unable to open the hostfile:
>>>> > usr/local/etc/openmpi-default-hostfile
>>>> > Check to make sure the path and filename are correct.
>>>> > --------------------------------------------------------------------------
>>>> > [Mario.local:04300] [[114,0],0] ORTE_ERROR_LOG: Not found in file
>>>> > base/ras_base_allocate.c at line 186
>>>> > [Mario.local:04300] [[114,0],0] ORTE_ERROR_LOG: Not found in file
>>>> > base/plm_base_launch_support.c at line 72
>>>> > [Mario.local:04300] [[114,0],0] ORTE_ERROR_LOG: Not found in file
>>>> > plm_rsh_module.c at line 990
>>>> > --------------------------------------------------------------------------
>>>> > A daemon (pid unknown) died unexpectedly on signal 1 while attempting
>>>> > to
>>>> > launch so we are aborting.
>>>> >
>>>> >
>>>> > There may be more information reported by the environment (see above).
>>>> >
>>>> >
>>>> > This may be because the daemon was unable to find all the needed
>>>> > shared
>>>> > libraries on the remote node. You may set your LD_LIBRARY_PATH to have
>>>> > the
>>>> > location of the shared libraries on the remote nodes and this will
>>>> > automatically be forwarded to the remote nodes.
>>>> > --------------------------------------------------------------------------
>>>> > --------------------------------------------------------------------------
>>>> > mpirun noticed that the job aborted, but has no info as to the process
>>>> > that caused that situation.
>>>> > --------------------------------------------------------------------------
>>>> > mpirun: clean termination accomplished
>>>> >
>>>> >
>>>> >
>>>> >
>>>> > ps. PTP is a parallel tools platform plugin for eclipse
>>>> >
>>>> >
>>>> > Regards,
>>>> >
>>>> >
>>>> > Mario
>>>> >
>>>> > _______________________________________________
>>>> > users mailing list
>>>> > users_at_[hidden]
>>>> > http://www.open-mpi.org/mailman/listinfo.cgi/users
>>>>
>>>>
>>>> --
>>>> Kind regards,
>>>> Timur Magomedov
>>>> Senior C++ Developer
>>>> DevelopOnBox LLC / Zodiac Interactive
>>>> http://www.zodiac.tv/
>>>>
>>>> _______________________________________________
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