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environment saves trace data in the TNF data file — making it available for analysis
in tnfview, the Prism environment merges all of the trace data from multiple data
buffers. The Prism environment merges trace data only when the program has run to
completion or when tnfview has been invoked. Therefore, if you collect trace data
in one session (without letting the program run to completion) and expect to view
that data in a later session, your data will not be merged and saved in your trace
data file.
Displaying Performance Data
The tnfview program supplies several different ways to view TNF probe data. You
start tnfview by selecting Display TNF Data from the Performance menu, or by
issuing the tnfview command from the Prism environment command line. For
example,
(prism all) tnfview myfile.tnf
You do not need to specify a file name as an argument to the tnfview command
unless you want to select an alternative TNF data file, created earlier or in another
session. The Prism environment will remember the TNF data file name created most
recently during the current session.
The main window of tnfview displays a timeline view of the TNF probe trace data.
A secondary window, the plot window, displays several graphical views of datasets
that you can create from the probe trace data. The three views provided by the plot
window are:
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Scatter plot view
Table view
Histogram view
FIGURE 6-1 shows the main window of the TNF Viewer with a 16-process MPI
program loaded. It is within this window that you examine the sequences of events,
displayed as colored shapes, that make up your program’s execution. This window
requires you to operate primarily with a mouse.
Chapter 6
Obtaining MPI Performance Data
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