HP DCPI tool

dcpiwhatcg(1)

NAME

dcpiwhatcg - Where Have All The Cycles Gone (on Alpha 21064/EV4 and 21164/EV5 processors)

SYNOPSIS

dcpiwhatcg [<flags>] image-file [image-file ...]

DESCRIPTION

Given one or more image-files and some profile files, dcpiwhatcg identifies what percent of the CYCLES samples were spent executing instructions vs. waiting for stalls of various categories. The output format 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. See dcpicalc(1) for a detailed discussion on interpreting the output.

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".

FLAGS

-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.

EXECUTION COUNT AND STALL ANALYSIS FLAGS

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 conjunction with -tab and -xct.

PROFILE SELECTION 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. 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 oldest epoch if -epoch latest-2 is specified.

-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 June 11, 2002 at 22:33 would be named 200206112233. 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.

-epoch all

Search for profile files in all epochs.

-ihost <hostnames...> --

Include just those profile files associated with the specified host names. The list of host names must be terminated either via -- or by the end of the option list. The command prints an error message and fails if both the -ihost and -ehost options are specified.

-ehost <hostnames...> --

Exclude any profile files associated with the specified host names. The list of host names must be terminated either via -- or by the end of the option list. The command prints an error message and fails if both the -ihost and -ehost options are specified.

-label <label>

Search for profile files with the specified label(s) (see dcpilabel(1)). This option can be repeated multiple times. If no labels are specified on the command line, profile file labels are ignored entirely. If any labels are specified on the command line, 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 the automatic profile lookup mechanism, or explicitly name the profile file with the -profile option; but don't do both.)

PROFILE SORTING FLAGS

[-s | -st | -sp] statistic

The named statistic is used to sort the profile output. For -s or -st, the statistic is assumed to be an aggregate event; for -sp it is assumed to be a ProfileMe statistic. If this option is not specified, the output is sorted so that the procedure or image that accounts for the most cycles is listed first; if the database contains ProfileMe statistics, the sort key is valid:retdelay, and otherwise the sort key is cycles. If neither of these statistics appears in the output, the first column in the output is used as the sort key. If this option is specified, the statistic specified as the sort key does not need to be listed explicitly in a -event or -pm specification; it will be included automatically.

TYPICAL USAGE

dcpiwhatcg -db db /vmunix 
dcpiwhatcg -db db -events cycles /vmunix
dcpiwhatcg -db db -stall "ITB/I-cache miss" myprog
dcpiwhatcg -db db -stall Slotting /vmunix

LIMITATIONS

Dcpiwhatcg works only on Alpha 21064/EV4 and 21164/EV5 processors. For Alpha 21264a/EV67 and later processors, use insights gained from the ProfileMe statistics instead.

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.

SEE ALSO

dcpi(1), dcpi2bb(1), dcpi2pix(1), dcpi2ps(1), dcpicalc(1), dcpicat(1), dcpicc(1), dcpicoverage(1), dcpictl(1), dcpid(1), dcpidiff(1), dcpidis(1), dcpiepoch(1), dcpiflow(1), dcpiflush(1), dcpikdiff(1), dcpilabel(1), dcpildlatency(1), dcpilist(1), dcpiprof(1), dcpiprofileme(1), dcpiquit(1), dcpiscan(1), dcpisource(1), dcpistats(1), dcpisumxct(1), dcpitar(1), dcpitopcounts(1), dcpitopstalls(1), dcpiuninstall(1), dcpiupcalls(1), dcpivarg(1), dcpivcat(1), dcpiversion(1), dcpivlst(1), dcpivprofiler(1), dcpix(1), dcpiformat(4), dcpiexclusions(4)

For more information, see the DCPI project home page http://h30097.www3.hp.com/dcpi.

COPYRIGHT

Copyright 1996-2004, Hewlett-Packard Company. All rights reserved.