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GPROF(1) GNU GPROF(1)
NAME
gprof - display call graph profile data
SYNOPSIS
gprof [ -[abcDhilLrsTvwxyz] ] [ -[ACeEfFJnNOpPqQZ][name] ]
[ -I dirs ] [ -d[num] ] [ -k from/to ]
[ -m min-count ] [ -R map_file ] [ -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 pro-
file 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 estab-
lishes 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 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 sym-
specs, 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.
"-I dirs"
"--directory-path=dirs"
The -I option specifies a list of search directories in which to find source
files. Environment variable GPROF_PATH can also be used to convey this infor-
mation. 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 rel-
ative 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.
"-t"
"--table-length=num"
The -t option causes the num most active source lines in each source file to be
listed when source annotation is enabled. The default is 10.
"-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 the file file-
name-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.
"-r"
"--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.
"-R map_file"
"--file-ordering map_file"
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 map_file 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 maybe_objc_method_name
c-lang.o:00000000 T print_lang_statistics
c-lang.o:00000000 T recognize_objc_keyword
c-decl.o:00000000 T print_lang_identifier
c-decl.o:00000000 T print_lang_type
...
To create a map_file with GNU "nm", type a command like "nm --extern-only
--defined-only -v --print-file-name 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 print-
ing 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 appro-
priate 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 heuris-
tic which examines the text space of the object file and identifies function
calls in the binary machine code. Since normal call graph records 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 com-
piled 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 func-
tions. 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 statis-
tical 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.
"-z"
"--display-unused-functions"
If you give the -z option, "gprof" will mention all functions in the flat pro-
file, 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.
"-h"
"--help"
The -h option prints command line usage.
"-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 con-
tains 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 function_name"
The -e function option tells "gprof" to not print information about the func-
tion function_name (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
function_name may be indicated with each -e option.
"-E function_name"
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 function_name may be indicated with each -E
option.
"-f function_name"
The -f function option causes "gprof" to limit the call graph to the function
function_name and its children (and their children...). More than one -f
option may be given; only one function_name may be indicated with each -f
option.
"-F function_name"
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 function_name 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 chil-
dren 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 execu-
tion of the profiling 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. McKu-
sick; 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 pub-
lished 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".
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