HP DCPI tool

dcpidiff(1)

NAME

dcpidiff - compare profiles for a procedure on Alpha 21064/EV4 and 21164/EV5 processors

SYNOPSIS

dcpidiff [global options] procedure-name -set [set options] image-name -set [set options] image-name

DESCRIPTION

Dcpidiff compares two sets of profiles for a procedure and prints out various statistics. It can compare the CPI, frequency, and static and dynamic stall cycles. If the images for the two sets of profiles are the same, it compares them by basic block. If the images differ, it compares them by source line number.

For each basic block (or source line) it prints the normalized range (i.e. the difference between the values over the sum of the values, expressed as a percentage), the two values and the ratio of the values. All entries are sorted by the normalized range so that the focus is on the entries that differ the most. The available options for each of the two sets is similar to the options for dcpicalc(1).

FLAGS

Global Options

-help

Print out usage information.

-version

Print out the version number.

-verbose

Verbose. Print out additional information.

-source_line

Print out statistics by source line number. If the image-name of the two sets are the same, then the default is to print out the statistics by basic block. If the image-name is different, then the statistics can only be printed by source line number.

-compare type

Specify the kind of information compared. The type is a comma-separated list of the following keywords: cpi, frequency, stalls, static_stalls, dynamic_stalls or all. The default is to compare CPI only.

-set

Denote the start of a set of sample files. All samples within a set are combined, and samples across different sets are compared.

Set Options

-conf_low

Compare low, medium, and high-confidence data.

-conf_high

Compare only high-confidence data. (Default is to compare medium and high-confidence data).

-cross_procedure [optimistic | pessimistic | selective]

Choose what assumption to make when encountering a procedure call boundary 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, we assume that whatever happens outside the analyzed procedure can cause a dynamic stall inside it. With optimistic, we assume that it cannot. With selective, the assumption is based on standard procedure call convention. (The default is optimistic.)

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.)

STATISTIC SELECTION FLAGS

Different kinds of performance counter statistics are available on various models of Alpha CPUs. Alpha 21064/EV4, 21164/EV5 and 21264/EV6 CPUs have traditional aggregate event counters. Alpha 21264A/EV67 and later processors have a mix of some traditional aggregate event counters and newer ProfileMe counters which allow accurate and precise instruction execution profiles on out-of-order processors. (See dcpiprofileme(1) for more information on ProfileMe statistics.)

The default statistic selection on an aggregate counter machine is to select all the aggregate events. The default on a ProfileMe machine is to select ProfileMe retire delay, retire count, !retired (i.e. aborted) count, !notrap (i.e. trap) count, and aggregate cycles.

The options below can be used to select various statistics when available. Use -event for aggregate statistics and -pm for ProfileMe statistics. Note: there can be multiple, mixed -event and -pm specifications. You can also specify the ratio of two statistics (written as stat1::stat2).

-pm pm_stat(+pm_stat)

Select the specified ProfileMe statistic plus any added in by optional +pm_stat specifications. For example, select various trap statistics by specifying the option -pm trap+replays+ldstorder+mispredict.

-pm default(+pm_stat)

Select the default set of ProfileMe statistics plus those added in by +pm_stat specifications. At least one additional statistic is mandatory; -pm default without modifications is extraneous and not allowed. The additional ProfileMe statistics will take the place of the aggregate cycles statistic which is selected by default.

-pm all(-pm_stat)

Select all ProfileMe statistics less those subtracted out. You can repeat the optional -pm_stat specification to deselect multiple ProfileMe statistics. Note: there are a lot of ProfileMe statistics. Unless you deselect a bunch of them, this will select more statistics than are appropriate for human consumption.

-event ag_stat(+ag_stat)

Select the specified aggregate statistic plus any added in by optional +ag_stat specifications. For example, select cycles, icache misses, and data cache misses when the option -event cycles+imiss+dmiss is specified.

-event all(-ag_stat)

Select all aggregate statistics less those subtracted out. You can repeat the optional -ag_stat specification to deselect multiple aggregate statistics.

-allevents

Select profile events corresponding to all event types, both aggregate and ProfileMe. However, if there are ProfileMe events, this will produce a large number of statistics, which in most cases will not be useful.

EXAMPLE USAGE

dcpidiff the_proc -set <image-name> -epoch latest -set <image-name> -epoch latest-1

Use dcpidiff to compare the CPI of procedure the_proc in two different sets of sample files.

dcpidiff -compare frequency the_proc -set <image-name> -epoch latest -set -xct the_program.xct -tab the_program.tab <image-name> -epoch latest-1

Use dcpidiff to compare the basic block frequencies in procedure the_proc as estimated by the dcpi tools, against the frequencies computed by the dcpix(1).

LIMITATIONS

Dcpidiff works only on Alpha 21064/EV4 and 21164/EV5 processors.

SEE ALSO

dcpi(1), dcpi2bb(1), dcpi2pix(1), dcpi2ps(1), dcpicalc(1), dcpicat(1), dcpicc(1), dcpicoverage(1), dcpictl(1), dcpid(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), dcpiwhatcg(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.