CHAPTER 4. PERFORMANCE DATA VISUALIZATION
Figure 4.13: Process Summary
It is possible to profile only one function or function group or to hide arbitrary functions
and function groups from the displayed information. To mark the function or function
group to be profiled or filtered just click on the associated color representation in the
chart. The context menu entries “Profile of Selected Function/(Group)” and “Filter Se-
lected Function/(Group)” will then provide the possibility to profile or filter the selected
function or function group. Using the “Process Filter” (see Section 4.4) allows you to
restrict this view to a set of processes.
The context menu entry “Sort by” allows you to order function profiles by “Number
of Clusters”. This option is only available if the chart is currently showing clusters.
Otherwise function profiles are sorted automatically by process. While profiling one
function the menu entry “Sort by Value” allows to order functions by their execution
time.
4.2.3 Message Summary
The “Message Summary” is a statistical chart showing an overview of all messages
grouped by certain characteristics, Figure 4.14.
All values are represented in a bar chart fashion. The number next to each bar is the
group base while the number inside a bar depicts the values depending on the chosen
metric. Therefore, the “Set Metric” sub-menu of the context menu can be used to switch
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4.2. STATISTICAL CHARTS
Figure 4.14: Message Summary Chart with metric set to “Message Transfer Rate”
showing the average transfer rate (A), and the minimal/maximal transfer
rate (B)
between “Aggregated Message Volume”, “Message Size”, “Number of Messages”, and
“Message Transfer Rate”.
The group base can be selected via the context menu entry “Group By”. Possible
options are “Message Size”, “Message Tag”, and “Communicator (MPI)”.
Note: There will be one bar for every occurring group. However, if the metric is set
to “Message Transfer Rate”, the minimal and the maximal transfer rate is given in an
additional small bar beneath the main bar showing the average transfer rate. The
additional bar starts at the minimal rate and ends at the maximal rate, see Figure 4.14.
In order to filter out messages click on the associated label or color representation in
the chart and then choose “Filter” from the context menu.
4.2.4 Communication Matrix View
The “Communication Matrix View” is another way of analyzing communication imbal-
ances. It shows information about messages sent between processes.
The chart, as shown in Figure 4.15, is figured as a table. Its rows represent the sending
processes whereas the columns represent the receivers. The color legend on the right
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CHAPTER 4. PERFORMANCE DATA VISUALIZATION
Figure 4.15: Communication Matrix View
indicates the displayed values. It adapts automatically to the currently shown value
range.
It is possible to change the type of displayed values. Different metrics like the aver-
age duration of messages passed from sender to recipient or minimum and maximum
bandwidth are offered. To change the type of value that is displayed use the context
menu option “Set Metric”.
Use the “Process Filter” to define which processes/groups should be displayed. (see
Section 4.4).
Note: A high duration is not automatically caused by a slow communication path be-
tween two processes, but can also be due to the fact that the time between starting
transmission and successful reception of the message can be increased by a recipient
that delays reception for some reason. This will cause the duration to increase (by this
delay) and the message rate, which is the size of the message divided by the duration,
to decrease accordingly.
4.2.5 I/O Summary
The “I/O Summary”, depicted in Figure 4.16, is a statistical chart giving an overview of
the input-/output operations recorded in the trace file.
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4.2. STATISTICAL CHARTS
Figure 4.16: I/O Summary
All values are represented in a histogram like fashion. The text label indicates the group
base while the number inside each bar represents the value of the chosen metric. The
“Set Metric” sub-menu of the context menu is used to switch between the available met-
rics “Number of I/O Operations”, “Accumulated I/O Transaction Sizes”, and all ranges
of “I/O Operation Size”, “I/O Transaction Time”, or “I/O Bandwidth”.
The I/O operations can be grouped by the characteristics “Transaction Size”, “File
Name”, and “Operation Type”. The group base can be changed via the context menu
entry “Group I/O Operations by”.
Note: There will be one bar for every occurring metric. For a quick and convenient
overview it is also possible to show minimum, maximum, and average values at once.
This option is available for the metrics “Transaction Size Range of I/O Operations”,
“Time Range of I/O Operations”, and “Bandwidth Range of I/O Operations”. The min-
imum and maximum values are shown in an additional, smaller bar beneath the main
bar indicating the average value. The additional bar starts at the minimum and ends at
the maximum value of the metric, see Figure 4.14.
In order to select the I/O operation types that should be considered for the statistic
calculation use the “Set I/O Operations” sub-menu of the context menu. Available
options are “Read”, “Write”, “Read, Write”, and “Apply Global I/O Operations Filter”.
The latter includes all selected operation types from the “I/O Events” filter dialog, see
Chapter 4.4.
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