dpat(1)

NAME

dpat − monitor and analyze program performance

SYNOPSIS

dpat [X_options] dpat −text dpat −dpat_command

DESCRIPTION

dpat (Distributed Performance Analysis Tool), is an interactive tool that looks at the performance of programs at the procedure level.

Invoking DPAT

You can invoke dpat in any of three ways:

dpat [X_options]
Invokes the dpat graphical user interface and optionally overrides one or more of the default X display options.

dpat −text Invokes the dpat text interface and displays the dpat > command prompt. You can then enter any dpat commands you want.

dpat −dpat_command
Invokes dpat for the execution of a single command. Note that the command must be preceded by the hyphen (−). The command can be followed by any of its valid command options. For example, dpat −analyze −data datafile analyzes the specified datafile and returns you to the shell prompt.

DPAT Functions

The Monitor function periodically samples a process’s call/return stack while the process is executing. dpat collects the samples in memory and writes them to a datafile when you exit from dpat. You can specify a file to use or you can accept the dpat default file. The default file is stored in your current working directory and, by default, is named datafile. For the target process, you can select an existing process, the next process to start on your machine, or a process that you explicitly invoke. You can also select either or both of two display options. The Traceback option provides a dynamic traceback, showing the currently active procedures. The Barcharts option presents one or two bar charts that show the most active procedures. To monitor a program with dpat, you do not have to compile it with any special options. The Analyze function produces reports on the contents of a datafile. You can select either a flat report or a hierarchical report. A flat report lists the procedures that appear in the datafile samples. The procedures are sorted in descending order according to the number of samples in which they appear. For each procedure, two percentages are given. One percentage reflects the time spent ’in only’ the procedure. The other reflects the time spent ’in or under’ the procedure. You can use a flat report to determine how much of the total execution time is consumed by specific procedures. A hierarchical report shows the dynamic calling structure of the process. For a given procedure, the report shows each calling context (call chain) in which the procedure appears. For each calling context, two percentages are given. One percentage reflects the time spent ’in only’ that context. The other reflects the time spent ’in or under’ that context -- that is, in procedures further down the call tree. You can use a hierarchical report to produce a structured breakdown of where the process spends its time. The View function displays a process’s call structure during real-time execution. Like the Monitor function, the View function samples the process’s call/return stack while the process is executing. However, for each sample taken, it simply displays the procedure that is active. It does not collect the samples in a datafile for later analysis. The Playback function replays the dynamic call sequence for a process. Like the Analyze function, the Playback function requires a saved datafile from a monitoring session. It provides a finer granularity than does the Analyze function. Specifically, it allows you to examine the contents of individual samples from the datafile. You can step forward or backward through the datafile sample by sample. You can also position on a portion of the datafile by specifying a sample number or by supplying a particular call sequence (call chain filter). Finally, you can request a flow graph that shows the call sequence leading up to the current sample.

Options

X_options One or more of the standard X command line options. Valid X command line options include: −background, −foreground, −display, −synchronous, and -reverse. (See The X Window System Programming and Applications, D. A. Young.)

-text Invokes the dpat text interface.

-dpat_command
Any valid dpat command, as documented in Appendix B of the Analyzing Program Performance with HP/PAK manual. Note that the command must be preceded by the hyphen (−).

INTERFACES

dpat supports three different interfaces. Which interface is used is determined by how you invoke dpat. The dpat graphical user interface uses OSF/Motif standards and is easy to use. Each dpat window provides a help button that supplies information about a command or aspect of dpat. To select an item using the graphical interface, place the cursor on it and press the left mouse button. For more information on the dpat graphical interface, refer to the Analyzing Program Performance with HP/PAK manual. The dpat text-based interface is a command line interface. dpat displays the prompt "dpat>". To get information on the commands you can issue using the text interface, enter help from the prompt. To get help on a specific command, enter help command_name (for example, help analyze). You can also execute individual dpat functions without invoking either the graphical or the text interface. For example, to get information about commands, enter dpat −help from the shell prompt. The valid dpat commands and their options are described in Appendix B of the Analyzing Program Performance with HP/PAK manual.

EXAMPLES

This example shows how to invoke the dpat graphical user interface. dpat This examples shows how to invoke the dpat text interface. dpat −text This example invokes dpat for one execution of the Monitor function. It instructs Monitor to monitor process_17 and save the collected data in the file ’my_data’. dpat −monitor process_17 −datafile my_data This example invokes dpat for one execution of the View function, to examine the real-time call structure for process_19. dpat −view process_19

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