CFD Online Discussion Forums - communication type blocking and non-blocking

You can change it in the controlDict -- it's a flag. See https://openfoam.org/news/parallel-io/. Here's the relevant bit from the controlDict provided with the release.

Code:

OptimisationSwitches

{

    // On NFS mounted file system: maximum wait for files to appear/get

    // updated. Set to 0 on distributed case.

    fileModificationSkew 10;



    //- Modification checking:

    //  - timeStamp         : use modification time on file

    //  - inotify           : use inotify framework

    //  - timeStampMaster   : do time stamp (and file reading) only on master.

    //  - inotifyMaster     : do inotify (and file reading) only on master.

    fileModificationChecking timeStampMaster;



    //- Parallel IO file handler

    //  uncollated (default), collated or masterUncollated

    fileHandler uncollated;



    //- collated: thread buffer size for queued file writes.

    //  If set to 0 or not sufficient for the file size threading is not used.

    //  Default: 2e9

    maxThreadFileBufferSize 2e9;



    //- masterUncollated: non-blocking buffer size.

    //  If the file exceeds this buffer size scheduled transfer is used.

    //  Default: 2e9

    maxMasterFileBufferSize 2e9;



    commsType       nonBlocking; // scheduled; // blocking;

    floatTransfer   0;

    nProcsSimpleSum 0;



    // Force dumping (at next timestep) upon signal (-1 to disable)

    writeNowSignal              -1; // 10;



    // Force dumping (at next timestep) upon signal (-1 to disable) and exit

    stopAtWriteNowSignal        -1;

}

Caelan