HP OpenVMS Systems

dcpitopstalls(1)

NAME

dcpitopstalls - Lists the instructions with the most stall cycles

SYNOPSIS

dcpitopstalls [<options>] image-file [image-file ...]

DESCRIPTION

Given one or more image-files and some profile files, dcpitopstalls identifies the N instructions in the images responsible for the most stall cycles. N defaults to 100.

The output has the form:

1104066 samples (99.99% of all samples) had frequency conf >= medium confidence.
728719 stall cycles with frequency conf >= medium confidence.
Stall cycles of conf >= medium confidence represent 65.99% of all samples.

top 10 stalls of length >= 0:
     %  cum% cycles  freq C   avg blame pc          procedure  file:line
 10.0% 10.0% 109885  4998 H  22.0     d 0x12000957c compress   compress.c:484
  9.9% 19.8% 108776  5513 H  19.7     d 0x120009530 compress   compress.c:477
  7.8% 27.6%  85668  3836 H  22.3     d 0x12000959c compress   compress.c:488
  3.0% 30.6%  33412  5513 H   6.1     ? 0x120009518 compress   compress.c:467
  2.0% 32.6%  22153  2343 H   9.5     d 0x120010fb4 decompress compress.c:731
  1.3% 33.9%  14169  2343 H   6.0   dDw 0x120010fa8 decompress compress.c:728
  1.3% 35.2%  14102  5513 H   2.6     I 0x120009638 compress   compress.c:510
  1.0% 36.2%  11385  1516 H   7.5     d 0x120010fd8 decompress compress.c:728
  0.9% 37.1%   9861  2343 H   4.2     p 0x120009558 compress   compress.c:481

In the listing, each line covers one instruction. The "%" column is the percentage of all cycles samples that were charged to stalls at the instruction. The "cum%" column is a running total of the "%" column. The "cycles" column is the number of cycles samples attributed to stalls. The "freq" column is the execution frequency of the instruction. The "C" column is the confidence level of the frequency: 'L' for low, 'M' for medium, and 'H' for high confidence. The "avg" column is the average length of the stall (= cycles / freq). The "blame" column identifies the possible causes for the stall using the same 1-character codes as dcpicalc(1). The "pc" column is the PC of the instruction. The "procedure" column is the name of the procedure containing the instruction or, if the name has been stripped, procedure's entry address. If more than one image-file is supplied, an additional column identifies which image contains the procedure. The "file:line" column is the source file name and line number associated with the instruction.

Note:  This command can only be used on aggregate (versus ProfileMe) data.

FLAGS

-help

Print information about options.

-min int

Specifies the minimum average stall length; stalls of fewer cycles will be tallied but not listed. Defaults to 0.

-n int

Specifies the maximum number of instructions to list. Defaults to 100.

-no_src

Omit the file:line column so that the output is more likely to fit in 80 columns.

-version

Print program version information.

-csl

Prints out only column names and data as comma-separated lists (importable by Excel). 

FREQUENCY AND STALL ANALYSIS FLAGS

The following options can be used to control the heuristics for estimating execution frequencies and identifying the causes of stalls.

-conf_low

Generate low, medium, and high confidence data.

-conf_med

Generate medium and high confidence data. (default)

-conf_high

Generate only high confidence data.

-cross_procedure [optimistic | pessimistic | selective]

Choose what assumption to make when a procedure call boundary is encountered while looking for reasons to explain dynamic stalls. A procedure call boundary is either a call made by the procedure being analyzed or the beginning or end of that procedure. With pessimistic, assume that whatever happens outside the analyzed procedure can cause a dynamic stall inside it. With optimistic, assume that it cannot. With selective, the assumption is based on standard procedure call convention. (The default is optimistic.)

-do_gp

Use a (non-linear time) constraint solver to exploit global flow constraints when estimating execution frequencies. The frequency estimates may still violate flow constraints.

PROFILE FILE FLAGS

By default, this command automatically finds all of the relevant profile files. The following options can be used to guide the search for the profile files.

-db <directory name>

Search for profile files in the specified profile database directory. The directory name should be the same name as the one specified when dcpid was started. That is, the named directory should contain a set of epochs. If this option is not specified, the directory name is obtained from the DCPIDB logical name. If neither of these methods succeeds in finding the appropriate directory, and no explicit set of profile files is provided via the -profiles option, then the command fails.

-epoch latest

Search for profile files in the latest epoch. This is the default.

-epoch latest-k

Search for profile files in the "k+1"th oldest epoch. For example, search in the third last epoch if "-epoch latest-2" is specified.

-epoch all

Search for profile files in all epochs.

-epoch <name>

Search for profile files in the named epoch. The epoch name should be the name of a subdirectory corresponding to a single epoch within the profile database directory. Epoch subdirectory names usually take the form YYYYMMDDHHMM (year-month-day-hours-minutes). For example, an epoch started on December 4, 2002 at 23:34 is named 200212042334. If an epoch is given a symbolic name by creating a symbol link to the actual epoch directory, then the symbolic name can also be used as an argument to the -epoch option.

-events all

Search for profile files corresponding to all event types such as cycles, icache misses, branch mispredictions, etc. This is the default.

-events type(+type)*

Search for profiles files for the specified event types. For example, search for cycles, icache misses, and data cache misses when the option -events cycles+imiss+dmiss is specified.

-events all(-type)*

Search for profile files for all event types except for the specified types. For example, search for all event types except for branch mispredictions when the option -events all-branchmp is specified.

-label <label>

Search for profile files with the specified label (see dcpilabel). If no labels are specified on the command line, profile file labels are ignored entirely. If any labels are specified on the command line (this option can be repeated several times), only profile files that have one of the specified labels are used.

-profiles <file names...> --

Use just the profile files named by the specified file names. The list of profile file names can be terminated either via --, or by the end of the option list. The command prints an error message and fails if the -profiles option is used in conjunction with any of the earlier automatic profile finding options. (Use either the automatic profile lookup mechanism, or explicitly name the profile file with the -profile option, but not both.)

TYPICAL USAGE

dcpitopstalls myprog.exe
dcpitopstalls -conf_low -n 50 -min 3 myprog.exe

LIMITATIONS

The source file name and line number information, which is extracted from the symbol table, is inaccurate for some optimized programs.

Because an internal HP DCPI interface was not designed for whole-program analysis, the running time of this program is quadratic rather than linear in size of the image file. Thus, this program runs slowly on large image files.

This command can only be used on aggregate (versus ProfileMe) data.

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).