Prism 6.0 User's Guide

Displaying Message Fields

Click individual messages to open the Message dialog box, shown in Figure 5-25.

Figure 5-25 Message Dialog Box

The fields in the Message dialog box are described in Table 5-3.

Table 5-3 Message Dialog Box Fields


Label	Description
Buffer	The address of the message.
Size	The length (in bytes) of the message.
Tag	The MPI tag argument passed in the call to post the message.
Comm	The name of the MPI communicator in which the message belongs, or the communicator's address if it is unnamed. Click on the Communicator View button to display the Communicator dialog box.
To	The rank of the destination of the message. Prism displays this field only for posted sends.
From	The rank of the sender of the message. Prism displays this field only for posted receives or unexpected receives.
Protocol	The implementation method by which the message has been sent. Possible values are: loopback, shared memory, RSM, and TCP.
Data Type	The MPI data type of the message, with the size of a single data type element in bytes. Click on the Data Type View button to display the Data Type dialog box. See "Data Types" for more information about the Data Type dialog box.The View button is available only for user-defined data types.
Contents	The contents of the message. Click on the triangular button to open or close the contents area. Click on More repeatedly to scroll through more of the message, until the whole message has been displayed.

When the Message dialog box displays a posted receive, it displays the value of the buffer address as null (indicating that no buffer has been allocated), and disables the Contents button.

When the Message dialog box displays an unexpected receive, it shows the delivered message with no data type. This characteristic is due to MPI design, since a posted receive declares the data type. Here too, the Contents button is disabled, and the visualizer displays the value of the buffer address as null.