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dcpi2bb(1)
NAME
dcpi2bb - Insert DCPI profile feedback data in an image file
SYNOPSIS
dcpi2bb [-make_bbdb] [-counts] [-pm all] [-load_lat] [<flags>] image-file
DESCRIPTION
Dcpi2bb inserts profile feedback information into an optional part of the
executable image for subsequent use by compilers or post-link optimizers
like spike(1). If the image was originally compiled
with the -feedback option, the compiler will have included an empty basic
block data base in the executable. If the image was not compiled for feedback,
dcpi2bb can create a basic block data base before inserting profile data.
One must gather profile samples using dcpid(1) before
using dcpi2bb. For best results, application training runs should be representative
of anticipated production runs. Note: Because DCPI has little overhead, it
is often practical to use actual production runs to generate profile feedback
information.
FLAGS
- -counts
- Populate the profile feedback data base with estimated execution frequency
counts for each basic block. Note: Because DCPI is a sampling tool, there
will be some statistical variation from run to run.
- -help
- Display a usage message.
- -load_lat
- Include load latency value samples (if available). These must
have been previously gathered by running dcpid(1) in
load latency value profiling mode. See dcpildlatency(1).
- -make_bbdb
- Create a basic block data base from the code structure and relocations
in the image.
- -scale
- By default, an estimated count of 1 denotes P executions,
where P is the average sampling period used to gather the
samples. With -scale, the estimated basic-block counts are
scaled by P.
- -trace flag
- Enable debug tracing for the specified
flag (e.g. alloc, change, check, combine,
esli, hash, io, leak, match, merge, name,
offset, profile, rank, reorder, weight).
- -version
- Print
dcpi2bb version
string.
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.
BUGS
Profiles gathered on an EV6 machine are not currently useful for profile
feedback. Because EV6 is an out-of-order machine without ProfileMe performance
counters, it is impractical to estimate basic block execution frequencies.
Use a 21264A/EV67 (or later) system to generate profile feedback data.
EXAMPLE
- dcpid db; run image; dcpiflush
- Profile image so DCPI can collect profile feedback data.
- dcpi2bb -db db -make_bbdb -counts -pm all image
- Run dcpi2bb to insert profile feedback data into executable image.
- spike image -feedback image -o image.faster
- Run spike(1) to analyze image based
on the profile feedback data stored in image and to create
a new, optimized image.faster.
SEE ALSO
dcpi(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), 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.
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