[Darshan-users] Data written to /dev/shm not captured by Darshan

[Phil Carns]

Hi Håkon,

Darshan is configured to automatically filter out access to certain 
types of file systems, one of which is tmpfs.  If you look in the 
darsan-runtime/lib/darshan-mpi-io.c file, there is a statement that 
looks like this:

     static char* fs_exclusions[] = {
         "tmpfs",
         "proc",
         "sysfs",
         "devpts",
         "binfmt_misc",
         ...

If you delete the "tmpfs" line and recompile Darshan then it should pick 
up the access to /dev/shm just like any other file system.

Unfortunately this is hard coded right now, but we can make this 
configurable in the future.

thanks,
-Phil

On 06/19/2012 02:50 AM, Håkon Strandenes wrote:
> Hello,
>
> I am trying to profile OpenFOAM (http://www.openfoam.com/) with 
> Darshan. This seems to work pretty good, although I have encountered a 
> little problem that I hope you could help me with:
>
> I am trying to write the data from each process to /dev/shm to reduce 
> the total filesystem IO (witch seems to be a bottleneck in some 
> cases). The problem is that Darshan does not capture this data, and 
> report 0 MB written to an unknown filesystem. See attached PDFs. The 
> case is identical except that in the first case (Normal.pdf) all 
> processes writes data to /home, and in the last case (DEV-SHM.pdf) 
> only a few files are read from /home, and the rest is read and written 
> from /dev/shm.
>
> Does any of you have some ideas why Darshan does not capture the data 
> written to/from /dev/shm?
>
> I have tried doing this on my workstation, with another version of 
> OpenFOAM (newer), and the same thing happens. OpenFOAM and Darshan is 
> in both cases compiled with the same compiler, Intel and GNU respectivly.
>
> Best regards,
> Håkon Strandenes
> Norwegian University of Science and Technology
>
>
> _______________________________________________
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> Darshan-users at lists.mcs.anl.gov
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