GNU GPROF(1)
NAME
gprof - display call graph profile data
SYNOPSIS
gprof [ -[abcDhilLsTvwxyz] ] [ -[ACeEfFJnNOpPqQZ][name] ]
[ -I dirs ] [ -d[num] ] [ -k from/to ]
[ -m min-count ] [ -t table-length ]
[ --[no-]annotated-source[=name] ]
[ --[no-]exec-counts[=name] ]
[ --[no-]flat-profile[=name] ] [ --[no-]graph[=name] ]
[ --[no-]time=name] [ --all-lines ] [ --brief ]
[ --debug[=level] ] [ --function-ordering ]
[ --file-ordering ] [ --directory-path=dirs ]
[ --display-unused-functions ] [ --file-format=name ]
[ --file-info ] [ --help ] [ --line ] [ --min-count=n ]
[ --no-static ] [ --print-path ] [ --separate-files ]
[ --static-call-graph ] [ --sum ] [ --table-length=len ]
[ --traditional ] [ --version ] [ --width=n ]
[ --ignore-non-functions ] [ --demangle[=STYLE] ]
[ --no-demangle ] [ image-file ] [ profile-file ... ]
DESCRIPTION
"gprof" produces an execution profile of C, Pascal, or
Fortran77 programs. The effect of called routines is
incorporated in the profile of each caller. The profile
data is taken from the call graph profile file (gmon.out
default) which is created by programs that are compiled with
the -pg option of "cc", "pc", and "f77". The -pg option
also links in versions of the library routines that are
compiled for profiling. "Gprof" reads the given object file
(the default is "a.out") and establishes the relation
between its symbol table and the call graph profile from
gmon.out. If more than one profile file is specified, the
"gprof" output shows the sum of the profile information in
the given profile files.
"Gprof" calculates the amount of time spent in each routine.
Next, these times are propagated along the edges of the call
graph. Cycles are discovered, and calls into a cycle are
made to share the time of the cycle.
Several forms of output are available from the analysis.
The flat profile shows how much time your program spent in
each function, and how many times that function was called.
If you simply want to know which functions burn most of the
cycles, it is stated concisely here.
The call graph shows, for each function, which functions
called it, which other functions it called, and how many
times. There is also an estimate of how much time was spent
in the subroutines of each function. This can suggest
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places where you might try to eliminate function calls that
use a lot of time.
The annotated source listing is a copy of the program's
source code, labeled with the number of times each line of
the program was executed.
OPTIONS
These options specify which of several output formats
"gprof" should produce.
Many of these options take an optional symspec to specify
functions to be included or excluded. These options can be
specified multiple times, with different symspecs, to
include or exclude sets of symbols.
Specifying any of these options overrides the default (-p
-q), which prints a flat profile and call graph analysis for
all functions.
"-A[symspec]"
"--annotated-source[=symspec]"
The -A option causes "gprof" to print annotated source
code. If symspec is specified, print output only for
matching symbols.
"-b"
"--brief"
If the -b option is given, "gprof" doesn't print the
verbose blurbs that try to explain the meaning of all of
the fields in the tables. This is useful if you intend
to print out the output, or are tired of seeing the
blurbs.
"-C[symspec]"
"--exec-counts[=symspec]"
The -C option causes "gprof" to print a tally of
functions and the number of times each was called. If
symspec is specified, print tally only for matching
symbols.
If the profile data file contains basic-block count
records, specifying the -l option, along with -C, will
cause basic-block execution counts to be tallied and
displayed.
"-i"
"--file-info"
The -i option causes "gprof" to display summary
information about the profile data file(s) and then
exit. The number of histogram, call graph, and basic-
block count records is displayed.
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"-I dirs"
"--directory-path=dirs"
The -I option specifies a list of search directories in
which to find source files. Environment variable
GPROFPATH can also be used to convey this information.
Used mostly for annotated source output.
"-J[symspec]"
"--no-annotated-source[=symspec]"
The -J option causes "gprof" not to print annotated
source code. If symspec is specified, "gprof" prints
annotated source, but excludes matching symbols.
"-L"
"--print-path"
Normally, source filenames are printed with the path
component suppressed. The -L option causes "gprof" to
print the full pathname of source filenames, which is
determined from symbolic debugging information in the
image file and is relative to the directory in which the
compiler was invoked.
"-p[symspec]"
"--flat-profile[=symspec]"
The -p option causes "gprof" to print a flat profile.
If symspec is specified, print flat profile only for
matching symbols.
"-P[symspec]"
"--no-flat-profile[=symspec]"
The -P option causes "gprof" to suppress printing a flat
profile. If symspec is specified, "gprof" prints a flat
profile, but excludes matching symbols.
"-q[symspec]"
"--graph[=symspec]"
The -q option causes "gprof" to print the call graph
analysis. If symspec is specified, print call graph
only for matching symbols and their children.
"-Q[symspec]"
"--no-graph[=symspec]"
The -Q option causes "gprof" to suppress printing the
call graph. If symspec is specified, "gprof" prints a
call graph, but excludes matching symbols.
"-y"
"--separate-files"
This option affects annotated source output only.
Normally, "gprof" prints annotated source files to
standard-output. If this option is specified, annotated
source for a file named path/filename is generated in
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the file filename-ann. If the underlying filesystem
would truncate filename-ann so that it overwrites the
original filename, "gprof" generates annotated source in
the file filename.ann instead (if the original file name
has an extension, that extension is replaced with .ann).
"-Z[symspec]"
"--no-exec-counts[=symspec]"
The -Z option causes "gprof" not to print a tally of
functions and the number of times each was called. If
symspec is specified, print tally, but exclude matching
symbols.
"--function-ordering"
The --function-ordering option causes "gprof" to print a
suggested function ordering for the program based on
profiling data. This option suggests an ordering which
may improve paging, tlb and cache behavior for the
program on systems which support arbitrary ordering of
functions in an executable.
The exact details of how to force the linker to place
functions in a particular order is system dependent and
out of the scope of this manual.
"--file-ordering mapfile"
The --file-ordering option causes "gprof" to print a
suggested .o link line ordering for the program based on
profiling data. This option suggests an ordering which
may improve paging, tlb and cache behavior for the
program on systems which do not support arbitrary
ordering of functions in an executable.
Use of the -a argument is highly recommended with this
option.
The mapfile argument is a pathname to a file which
provides function name to object file mappings. The
format of the file is similar to the output of the
program "nm".
c-parse.o:00000000 T yyparse
c-parse.o:00000004 C yyerrflag
c-lang.o:00000000 T maybeobjcmethodname
c-lang.o:00000000 T printlangstatistics
c-lang.o:00000000 T recognizeobjckeyword
c-decl.o:00000000 T printlangidentifier
c-decl.o:00000000 T printlangtype
...
To create a mapfile with GNU "nm", type a command like
"nm --extern-only --defined-only -v --print-file-name
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program-name".
"-T"
"--traditional"
The -T option causes "gprof" to print its output in
``traditional'' BSD style.
"-w width"
"--width=width"
Sets width of output lines to width. Currently only
used when printing the function index at the bottom of
the call graph.
"-x"
"--all-lines"
This option affects annotated source output only. By
default, only the lines at the beginning of a basic-
block are annotated. If this option is specified, every
line in a basic-block is annotated by repeating the
annotation for the first line. This behavior is similar
to "tcov"'s -a.
"--demangle[=style]"
"--no-demangle"
These options control whether C] symbol names should be
demangled when printing output. The default is to
demangle symbols. The "--no-demangle" option may be
used to turn off demangling. Different compilers have
different mangling styles. The optional demangling
style argument can be used to choose an appropriate
demangling style for your compiler.
Analysis Options
"-a"
"--no-static"
The -a option causes "gprof" to suppress the printing of
statically declared (private) functions. (These are
functions whose names are not listed as global, and
which are not visible outside the file/function/block
where they were defined.) Time spent in these
functions, calls to/from them, etc, will all be
attributed to the function that was loaded directly
before it in the executable file. This option affects
both the flat profile and the call graph.
"-c"
"--static-call-graph"
The -c option causes the call graph of the program to be
augmented by a heuristic which examines the text space
of the object file and identifies function calls in the
binary machine code. Since normal call graph records
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are only generated when functions are entered, this
option identifies children that could have been called,
but never were. Calls to functions that were not
compiled with profiling enabled are also identified, but
only if symbol table entries are present for them.
Calls to dynamic library routines are typically not
found by this option. Parents or children identified
via this heuristic are indicated in the call graph with
call counts of 0.
"-D"
"--ignore-non-functions"
The -D option causes "gprof" to ignore symbols which are
not known to be functions. This option will give more
accurate profile data on systems where it is supported
(Solaris and HPUX for example).
"-k from/to"
The -k option allows you to delete from the call graph
any arcs from symbols matching symspec from to those
matching symspec to.
"-l"
"--line"
The -l option enables line-by-line profiling, which
causes histogram hits to be charged to individual source
code lines, instead of functions. If the program was
compiled with basic-block counting enabled, this option
will also identify how many times each line of code was
executed. While line-by-line profiling can help isolate
where in a large function a program is spending its
time, it also significantly increases the running time
of "gprof", and magnifies statistical inaccuracies.
"-m num"
"--min-count=num"
This option affects execution count output only.
Symbols that are executed less than num times are
suppressed.
"-n[symspec]"
"--time[=symspec]"
The -n option causes "gprof", in its call graph
analysis, to only propagate times for symbols matching
symspec.
"-N[symspec]"
"--no-time[=symspec]"
The -n option causes "gprof", in its call graph
analysis, not to propagate times for symbols matching
symspec.
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"-z"
"--display-unused-functions"
If you give the -z option, "gprof" will mention all
functions in the flat profile, even those that were
never called, and that had no time spent in them. This
is useful in conjunction with the -c option for
discovering which routines were never called.
Miscellaneous Options
"-d[num]"
"--debug[=num]"
The -d num option specifies debugging options. If num
is not specified, enable all debugging.
"-Oname"
"--file-format=name"
Selects the format of the profile data files.
Recognized formats are auto (the default), bsd, 4.4bsd,
magic, and prof (not yet supported).
"-s"
"--sum"
The -s option causes "gprof" to summarize the
information in the profile data files it read in, and
write out a profile data file called gmon.sum, which
contains all the information from the profile data files
that "gprof" read in. The file gmon.sum may be one of
the specified input files; the effect of this is to
merge the data in the other input files into gmon.sum.
Eventually you can run "gprof" again without -s to
analyze the cumulative data in the file gmon.sum.
"-v"
"--version"
The -v flag causes "gprof" to print the current version
number, and then exit.
Deprecated Options
These options have been replaced with newer versions
that use symspecs.
"-e functionname"
The -e function option tells "gprof" to not print
information about the function functionname (and its
children...) in the call graph. The function will still
be listed as a child of any functions that call it, but
its index number will be shown as [not printed]. More
than one -e option may be given; only one functionname
may be indicated with each -e option.
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"-E functionname"
The "-E function" option works like the "-e" option, but
time spent in the function (and children who were not
called from anywhere else), will not be used to compute
the percentages-of-time for the call graph. More than
one -E option may be given; only one functionname may
be indicated with each -E option.
"-f functionname"
The -f function option causes "gprof" to limit the call
graph to the function functionname and its children
(and their children...). More than one -f option may be
given; only one functionname may be indicated with each
-f option.
"-F functionname"
The -F function option works like the "-f" option, but
only time spent in the function and its children (and
their children...) will be used to determine total-time
and percentages-of-time for the call graph. More than
one -F option may be given; only one functionname may
be indicated with each -F option. The -F option
overrides the -E option.
FILES
"a.out"
the namelist and text space.
"gmon.out"
dynamic call graph and profile.
"gmon.sum"
summarized dynamic call graph and profile.
BUGS
The granularity of the sampling is shown, but remains
statistical at best. We assume that the time for each
execution of a function can be expressed by the total time
for the function divided by the number of times the function
is called. Thus the time propagated along the call graph
arcs to the function's parents is directly proportional to
the number of times that arc is traversed.
Parents that are not themselves profiled will have the time
of their profiled children propagated to them, but they will
appear to be spontaneously invoked in the call graph
listing, and will not have their time propagated further.
Similarly, signal catchers, even though profiled, will
appear to be spontaneous (although for more obscure
reasons). Any profiled children of signal catchers should
have their times propagated properly, unless the signal
catcher was invoked during the execution of the profiling
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routine, in which case all is lost.
The profiled program must call "exit"(2) or return normally
for the profiling information to be saved in the gmon.out
file.
SEE ALSO
monitor(3), profil(2), cc(1), prof(1), and the Info entry
for gprof.
``An Execution Profiler for Modular Programs'', by S.
Graham, P. Kessler, M. McKusick; Software - Practice and
Experience, Vol. 13, pp. 671-685, 1983.
``gprof: A Call Graph Execution Profiler'', by S. Graham, P.
Kessler, M. McKusick; Proceedings of the SIGPLAN '82
Symposium on Compiler Construction, SIGPLAN Notices, Vol.
17, No 6, pp. 120-126, June 1982.
COPYRIGHT
Copyright (C) 1988, 92, 97, 98, 99, 2000, 2001, 2003 Free
Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation
License, Version 1.1 or any later version published by the
Free Software Foundation; with no Invariant Sections, with
no Front-Cover Texts, and with no Back-Cover Texts. A copy
of the license is included in the section entitled "GNU Free
Documentation License".
ATRIBUTES
See attributes(5) for descriptions of the following
attributes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWbinutils
Interface Stability External
NOTES
Source for GNU binutils is available on
http:/opensolaris.org.
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