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Subject: Re: [OMPI users] sndlib problem by mpicc compiler
From: TERRY DONTJE (terry.dontje_at_[hidden])
Date: 2012-07-30 07:25:44

On 7/30/2012 6:11 AM, Pawe³ Jaromin wrote:
> Hello
> Thanks for fast answer, but the problem looks a little different.
> Of course, I use this code only for master node (rank 0), because only
> this node has an access to file.
> As You can see i use "if" clause to check sndFile for NULL:
> if (sndFile == NULL)
> and it returns not NULL value, so the code can run forward.
> I have found the problem during check array:
> long numFrames = sf_readf_float(sndFile, snd_buffor, sfinfo.frames);
> // Check correct number of samples loaded
> if (numFrames != sfinfo.frames) {
> fprintf(stderr, "Did not read enough frames for source\n");
> sf_close(sndFile);
> free(snd_buffor);
> MPI_Finalize();
> return 1;
> }
> So, after that I went to debuger to check variables (I use Eclipse PTP
> and sdm enviroment), then after inicjalization variable "sndFile" has
> "no value" not "NULL" . Unfortunatelly sndFile has still the same
> value to the end of program :(.
What do you mean by sndFile has "no value"? There isn't a special "no
value" value to a variable unless you are debugging a code that somehow
had some variable optimized out at the particular line you are
interested in.
> Declarations:
> FILE *outfile = NULL ;
> SF_INFO sfinfo ;
> SNDFILE *sndFile= NULL;
> Very interesting is , that "sfinfo" from the same library works perfect.
> At the end of this story, I modified the program without MPI , then
> compiled it by gcc (not mpicc) and it works fine (in debuger sndFile
> has proper value).
So it seems you believe mpicc is doing something wrong when all mpicc is
is a wrapper to a compiler. Maybe doing a "mpicc --showme" will give
you an idea what compiler and options mpicc is passing to the compiler.
This should give you an idea the difference between your gcc and mpicc
compilation. I would suspect either mpicc is using a compiler
significantly different than gcc or that mpicc might be passing some
optimization parameter that is messing the code execution (just a guess).
> I hope, now is clear.
Not really.

> 2012/7/30 TERRY DONTJE<terry.dontje_at_[hidden]>:
>> I am not sure I am understanding the problem correctly so let me describe it
>> back to you with a couple clarifications.
>> So your program using sf_open compiles successfully when using gcc and
>> mpicc. However, when you run the executable compiled using mpicc sndFile is
>> null?
>> If the above is right can you tell us how you ran the code?
>> Will the code run ok if ran with "mpirun -np 1" on the same machine you run
>> the gcc code normally?
>> When the mpicc compiled code sf_open call returns NULL what does the
>> successive sf_strerror report?
>> My wild guess is when you run the mpicc compiled code one of the processes
>> is on a node that doesn't have access to the file passed to sf_open.
>> --td
>> On 7/28/2012 1:08 PM, Pawe³ Jaromin wrote:
>> Hello all
>> Because I try make a program to parallel procesing sound files, I use
>> libsndfile library to load and write wav files. Sytuation is strange,
>> because when I compile the program by gcc is good (no parallel), but
>> if I do it by mpicc is a problem with sndFile variable.
>> // Open sound file
>> SF_INFO sndInfo;
>> SNDFILE *sndFile = sf_open(argv[1], SFM_READ,&sndInfo);
>> if (sndFile == NULL) {
>> fprintf(stderr, "Error reading source file '%s': %s\n", argv[1],
>> sf_strerror(sndFile));
>> return 1;
>> }
>> This code run witout an error, but variable is "No value"
>> Maybe somone can help me ??
>> --
>> Terry D. Dontje | Principal Software Engineer
>> Developer Tools Engineering | +1.781.442.2631
>> Oracle - Performance Technologies
>> 95 Network Drive, Burlington, MA 01803
>> Email terry.dontje_at_[hidden]
>> _______________________________________________
>> users mailing list
>> users_at_[hidden]

Terry D. Dontje | Principal Software Engineer
Developer Tools Engineering | +1.781.442.2631
Oracle *- Performance Technologies*
95 Network Drive, Burlington, MA 01803
Email terry.dontje_at_[hidden] <mailto:terry.dontje_at_[hidden]>