Using Open|SpeedShop™

Examples using Open|SpeedShop for Performance Analysis of Hybrid (MPI and openMP) applications

We have run Open|SpeedShop convenience script on the NPB-MZ BT program and created a database file that has 4 ranks each of which has 4 underlying openMP threads.

Within a terminal window, enter: 
openss -f bt-mz.B.4-pcsamp-1.openss

Changes have been added to Open|SpeedShop 2.0.1 to better support the analysis of hybrid applications which will be outlined below.

Here we show the aggregated results relative to statements in the application.  So, we are showing the statements that took the most time in the job.  For this execution of BT, statement 440 took the most time.  By double clicking on the statement Open|SpeedShop focuses on the source for that line of the application source and highlights that line.   Note, in this view we moved the ManageProcess tab to the lower panel and split the upper panel using the vertical splitter icon on the far right side of the original upper panel.

source view

  Here we used the ManageProcess panel to highlight one rank and an individual thread within the rank to show only that threads
  performance data in the Stats Panel view.    Note: Use the focus on threads and processes Manage Process panel option to
  focus on individual threads within a rank.    Right mouse button down on the Manage Process panel tab to see the options.

individual threads

  Here we used the ManageProcess panel to highlight one rank to show the data from all the threads that are executed under
  that particular rank in order to see the performance data in the Stats Panel view.    Note: Use the "focus on selected rank and underlying
  threads" Manage Process panel option to focus on all the threads within a rank.    Right mouse button down on the Manage Process
  panel tab to see the options.


Underlying threads view

Note:  Once you focus on individual or groups of ranks, e.g. venturing away from the default aggregated views, then you need to use
the "CL" clear auxillary setting icon to clear away all the optional selections and get back to looking at the aggregated results again.

clear icon

After clearing the specific rank and/or thread selections, we can click the "LB" load balance icon and Open|SpeedShop will display
the min, max, average values across all the ranks in the hybrid code.  This helps decide if there is imbalance across the ranks of
the hybrid application.   We can focus on individual ranks to see the balance across the openMP threads that are in an individual
rank (next example image).

LB aggregated

Here we used the Manage Process panel "Focus on selected rank and underlying threads" menu options to view the load balance
across the 4 openMP threads for the rank 0 process.

rank 0 openMP threads



Please also explore the various options offered via a panel's pull down menu. Further options can be accessed by clicking on a colored
downward-facing arrow or using the StatsPanel icons.  Red icons represent view options, such as updating the data or clearing the
view options. The "green" icons correspond to different possible views of the performance data.   The "dark blue" icons correspond
to analysis options while the "light blue" icon corresponds to information about the experiment.  There is context sensitive text that
is shown when you hover over the icons.

Thanks!

Please visit the Open|SpeedShop forum if you have questions:  Open|SpeedShop Forum.

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