Hi Rob, it is true that you can't easily see the offset with IPM,
unless you follow the sequence of writes or look for an fseek command.
I did have an earlier beta of IPM that wrapped lseek and lseek64, but
it looks like those did not make their way into the 2.0 beta. Also, an
important step I forgot to mention in my original email is that you
also have to specify a list of "wraps" when you link your application,
like this:

WRAPS = 
-Wl,-wrap,fopen,-wrap,fdopen,-wrap,freopen,-wrap,fclose,-wrap,fflush,-wrap,fread,-wrap,fwrite,-wrap,fseek,-wrap,ftell,-wrap,rewind,-wrap,fgetpos,-wrap,fsetpos,-wrap,fgetc,-wrap,getc,-wrap,ungetc,-wrap,read,-wrap,write,-wrap,open,-wrap,open64,-wrap,creat,-wrap,close,-wrap,truncate,-wrap,ftruncate,-wrap,truncate64,-wrap,ftruncate64
-Wl,-wrap,fopen,-wrap,fdopen,-wrap,freopen,-wrap,fclose,-wrap,fflush,-wrap,fread,-wrap,fwrite,-wrap,fseek,-wrap,ftell,-wrap,rewind,-wrap,fgetpos,-wrap,fsetpos,-wrap,fgetc,-wrap,getc,-wrap,ungetc,-wrap,read,-wrap,write,-wrap,open,-wrap,open64,-wrap,creat,-wrap,close,-wrap,truncate,-wrap,ftruncate,-wrap,truncate64,-wrap,ftruncate64

(link line ...) -lipm $(WRAPS)

The wraps show the full set of POSIX functions that IPM will trace.

Mark

On Fri, Mar 4, 2011 at 3:22 PM, Rob Latham <[email protected]> wrote:
> On Fri, Mar 04, 2011 at 10:09:14AM -0500, Mark Howison wrote:
>> Hi Matthieu,
>>
>> The Integrated Performance Monitor (IPM) v2 beta has a POSIX I/O
>> tracing feature. This will give you detailed output of the underlying
>> POSIX calls (such as open, write and read) made by your application
>> (through the pHDF layer). You can download it here:
>>
>> http://tools.pub.lab.nm.ifi.lmu.de/web/ipm/
>>
>> To enable I/O tracing, you have to configure with
>>
>> ./configure --enable-posixio CFLAGS=-DHAVE_POSIXIO_TRACE
>>
>> You have to relink your application against the libipm.a that his
>> produces (or you can enable the shared library and do an LD_PRELOAD).
>> After you application runs, you'll have a text file for each MPI rank
>> with the POSIX calls and their arguments.
>
> Matthieu Dorier was asking for a tuple of (rank,file,offset,size).
>
> I guess this really belongs on the ipm-hpc-help list, but IPM doesn't
> actually give you the offset information.   It wraps fseek(3) but HDF5
> using MPI-IO is probably going to call lseek(2), lseek64(2) some other
> seek-like system call.
>
> IPM is pretty close, giving the file, size, and a timestamp all tucked
> into a file-per-rank.
>
> ==rob
>
> --
> Rob Latham
> Mathematics and Computer Science Division
> Argonne National Lab, IL USA
>
> _______________________________________________
> Hdf-forum is for HDF software users discussion.
> [email protected]
> http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
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