1 PCA The Compaq Performance and Coverage Analyzer for OpenVMS (PCA) is a software development tool that helps you analyze the run- time behavior of application programs. PCA can pinpoint execution bottlenecks and other performance problems in user programs. Using this information, you can modify your programs to run faster. This tool also measures which parts of your program are or are not executed by a given set of test data so that you can devise tests that exercise all parts of your program. PCA has two operational components: the Collector and the Analyzer. The Collector gathers performance or coverage data on a running user program and writes that data to a performance data file. Later, the Analyzer processes the collected data to produce performance or coverage histograms and tables. The DCL command 'PCA' invokes the Analyzer. The parameter to the PCA command is the name of the performance data file to analyze. Format $ PCA [file-spec] 2 Parameters file-spec Specifies the performance data file to be analyzed. File-spec may be any valid OpenVMS file specification. If you omit the file type, .PCA is used by default. If you omit the entire file-spec parameter, you must use the Analyzer SET DATAFILE command to specify the performance data file. 2 Qualifiers /COMMAND /COMMAND="command [;command...]" Specifies a list of Analyzer commands. The Analyzer executes this list of commands after executing the commands in the initialization file (if any) and before prompting for commands from the terminal. /INTERFACE /INTERFACE=[interface-type] Controls the display interface to be selected. The default qualifier value is /INTERFACE=CHARACTER_CELL. Qualifier Keyword Description CHARACTER_CELL Selects the character cell interface. DECWINDOWS Selects the DECwindows (a.k.a Motif) interface, depending on the setting of the various PCA*$DEC$DISPLAY and DECW$DISPLAY logicals. MOTIF Selects the Motif (a.k.a DECwindows) interface, depending on the setting of the various PCA*$DEC$DISPLAY and DECW$DISPLAY logicals. 2 Collector The Collector gathers performance or coverage data from your program at run time and writes that data to a performance data file. To use the Collector, you must: 1. Compile your sources with the "/DEBUG" qualifier; This puts all the necessary symbolic information PCA needs into the object file. 2. The following steps specifies the PCA Collector as your program's "debugger": i Link your program with the "/DEBUG" qualifier; ii Define the logical name LIB$DEBUG as PCA$COLLECTOR; 3. Run your program; 4. Enter the "GO" command at the PCAC> prompt. The Collector will transfer control to your program just like the debugger does, and will store the data in a data file named your-image-name.PCA. The following example illustrates the DCL commands required to invoke the Collector on the FORTRAN program PRIMES.FOR: $ FORTRAN/DEBUG PRIMES.FOR $ LINK/DEBUG PRIMES.OBJ $ DEFINE LIB$DEBUG PCA$COLLECTOR $ RUN PRIMES.EXE Compaq Performance and Coverage Analyzer for OpenVMS Version V4.7-3 PCAC> When you get the Collector prompt (PCAC>), you have successfully invoked the Collector and are ready to enter Collector commands. To collect PC-sampling data, it is sufficient to enter the GO command at this point. The Collector will create a performance data file with the default name "image-name.PCA", where image- name is the name of the executable image being run. This file will contain the collected data and all symbol information needed by the Analyzer. PCAC> GO %PCA-I-DEFDATFIL, set datafile required in this context, creating '[]PRIMES.PCA' %PCA-I-BEGINCOL, data collection begins %PCA-I-DATADEFPC, defaulting to collecting PC sampling data %PCA-I-ENDCOL, data collection ends $ For more information, enter HELP at the PCAC> prompt. 2 Analyzer The Analyzer processes the data in a performance data file to produce histograms, tables, and other reports. The Analyzer enables you to interactively examine the gathered data in various ways until performance bottlenecks are pinpointed or code not covered by testing is identified. To invoke the Analyzer, use the PCA command at DCL level. This command accepts the name of a performance data file created by the Collector as a parameter. For example, to run the Analyzer on the performance data file PRIMES.PCA, use this command: $ PCA PRIMES Compaq Performance and Coverage Analyzer for OpenVMS Version V4.7-3 PCAA> The PCAA> prompt indicates that The Analyzer is ready to accept Analyzer commands. For example, the user may just enter the NEXT command at this point. It will display a source plot of the program's routine with the most PC-sampling data points. In the plot, the line with the most data points will be pointed to by an arrow (->). In other words, the NEXT command will show where the program is spending most of the execution time. PCAA> NEXT Compaq Performance and Coverage Analyzer for OpenVMS Page 1 Program Counter Sampling Data (192 data points total) - "*" Routine PRIME\PRIME Percent Count Line PRIME\PRIME\ 0.5% 5: LOGICAL FUNCTION PRIME(N) 1.6% 6: PRIME = .TRUE. 0.5% 7: DO 10 I = 2, N/2 54.7% ******* -> 8: IF ((N - ((N / I) * I)) .EQ. 0) THEN 9: PRIME = .FALSE. 0.0% 10: RETURN 0.0% 11: ENDIF 1.0% 12: 10 CONTINUE 0.0% 13: RETURN PCAA> The NEXT command can now be typed again to traverse to the point with the next largest number of data points, and so on. To end the Analyzer session, the EXIT command or Control/Z can be entered. For more information, enter HELP at the PCAA> prompt. 2 Release_Notes The release notes for PCA are located in SYS$HELP:PCAvvu.RELEASE_ NOTES (ASCII text) and SYS$HELP:PCAvvu_RELEASE_NOTES.PS (postscript), where 'vv' represents the major version number and 'u' the minor version number. For example, the filename for the PCA V4.7 release notes is 'PCA047.RELEASE_NOTES'.