HP OpenVMS Systems

dcpi(1)

NAME

dcpi - HP Digital Continuous Profiling Infrastructure

DESCRIPTION

The HP Digital Continuous Profiling Infrastructure (HP DCPI) system consists of a set of tools that provides low-overhead continuous profiling of all executables, including the kernel. It is based on periodic sampling using the Alpha performance counter hardware. Profiles containing samples for each executable image (including shared libraries) are stored in a user-specified directory.

Tools are provided to analyze profiles and produce a breakdown of all CPU time by image, and by procedure within images. In addition, detailed information can be produced showing the time spent executing each instruction in a procedure and the reasons for static and dynamic stalls.

Note that by default, input such as procedure names is in lower case. Where case is significant, enclose the procedure name in quotation marks (").

Note: Symbolic information is created for a program if the program is compiled with the /DEBUG qualifier, and if the program is linked with the /DEBUG or /DSF qualifier. If the /DSF qualifier is used to link the program, symbolic information is available if either of the following is true:

• The DSF file resides in the same directory as the program image
• Logical name DBG$IMAGE_DSF_PATH points to the directory in which the DSF file resides.

Without the symbolic information, the analysis tools can do only top level image analysis.

For more information, see the HP Digital Continuous Profiling Infrastructure home page.

TOOLS

Sampling Tools

dcpid

Continuous profiling daemon. Extracts raw samples from kernel device driver, associates them with executable images, and stores them in profiles on disk.

dcpictl

Controls the operation of dcpid. Additionally, dcpictl can be used to provide specific information to the DCPI daemon.

Analysis Tools

dcpicalc

Annotates each instruction in a procedure's basic-block graph with the average number of cycles for that instruction, and computes the overall average cycle-per-instruction for that procedure.

dcpiwhatcg

Produces, for one or more images, a summary breakdown of where time has been spent (percent of cycles spent in, for example, memory delays, static stalls, branch mispredicts, and useful execution).

dcpitopstalls

Produces a sorted list of the instructions accounting for the most stall cycles.

dcpidiff

Compares two sets of profiles for a procedure, highlighting basic blocks or source lines with the largest differences.

dcpi2ps

Formats a basic-block graph into PostScript.

dcpicat

Prints the contents of one or more profile files in an ASCII format.

dcpiprof

Analyzes profile data collected by dcpid. Produces a breakdown of samples by image, or by procedures within images. In the absence of symbolic information, dcpiprof accepts address range input such as 0x20100:0x20300.

dcpilist

Lists the contents of a procedure and annotate the listing with samples collected during profiling via dcpid. The listing can contain either machine instructions, or source lines, or both. The listing is annotated with the samples collected during profiling, as well as the average number of cycles required to execute each instruction or source line. In the absence of symbolic information, dcpiprof accepts address range input such as 0x20100:0x20300.

EXAMPLE USAGE

dcpiprof I

Use dcpiprof to analyze the breakdown of CPU time across all procedures in the image file I.

dcpilist -asm P I

Disassemble procedure P in the image file I, and annotate the disassembly with samples extracted from the profile database and the average cycle time required for executing each instruction.

dcpilist -source P I

Generate a source code listing of procedure P in the image file I, and annotate the listing with samples extracted from the profile database, and the average cycle time required for executing each source line.

INSTALLATION

Installation instructions are located at the DCPI installation page.

SEE ALSO

dcpi(1), dcpi2ps(1), dcpicat(1), dcpictl(1), dcpid(1), dcpidiff(1), dcpiformat(4), dcpilist(1), dcpiprof(1), dcpitopstalls(1), dcpiwhatcg(1)  

For more information, see the HP Digital Continuous Profiling Infrastructure project home page (http://h30097.www3.hp.com/dcpi).