dcpiwhatcg - Where Have All The Cycles Gone (for an image)
dcpiwhatcg [<options>] image-file [image-file ...]
Given one or more image-files and some profile files, dcpiwhatcg identifies what percent of the CYCLES samples that were spent executing instructions vs. waiting for stalls of various categories. The output is the same as the procedure-level output of dcpicalc(1), except that it covers all of the procedures in the image-files rather than a single procedure.
In addition, dcpiwhatcg optionally outputs a sorted list of the procedures that contain samples blamed on a particular kind of stall, e.g., "Branch mispredict".
- -help
- Print information about options.
- -pr
- Print a progress report line before analyzing each procedure.
- -stall stall-kind
- Output a sorted list of the procedures that contain samples blamed on stall-kind. Stall-kind must be the name of a specific dynamic or static stall as listed in the "Where have all the cycles gone?" output of dcpiwhatcg or dcpicalc(1). This option does not work for multiple image-files.
- -version
- Print program version information.
The following options can be used to control the heuristics for estimating execution counts 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 counts. The estimates may still violate flow constraints.
- -tab foo.tab
- Get execution counts from output of dcpix(1) instead of making estimates, which may be inaccurate. Requires a .xct file.
- -xct foo.xct
- Get execution counts from output of dcpix(1) instead of making estimates, which may be inaccurate. Requires a .tab file.
- -xct_factor num
- Scales counts from .xct files by num. Useful when you run a program once under dcpix(1) but multiple (num) times under dcpid(1) to get more samples. Used in conjuction with -tab and -xct.
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. I.e., the named directory should contain a set of epochs. If this option is not specified, the directory name is obtained from the DCPIDB environment variable. If neither this option, nor the DCPIDB environment variable are set, the name of the directory used by the last invocation of dcpid on this machine is used. If none of these methods succeed 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 YYMMDDHHMM (year-month-day-hours-minutes). For example, an epoch started on December 4, 1996 at 23:34 is named 9612042334. 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.)
Because an internal 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.
dcpi(1), dcpiflow(1), dcpiprof(1), dcpilist(1), dcpidis(1), dcpiscan(1), dcpiepoch(1), dcpiflush(1), dcpicalc(1), dcpilabel(1), dcpi2ps(1), dcpicat(1), dcpiquit(1), dcpidiff(1), dcpitopstalls(1), dcpictl(1), dcpisource(1), dcpicc(1), dcpiversion(1), dcpiuninstall(1), dcpi2pix(1), dcpikdiff(1), dcpix(1), dcpisumxct(1), dcpistats(1), dcpid(1), dcpiformat(4), dcpiloader(5)
For more information, see the DIGITAL Continuous Profiling Infrastructure project home page (http://www.research.digital.com/SRC/dcpi/ from outside DIGITAL).
Mark VandevoordeThis page was generated automatically by mtex software.