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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 map_file ] [ --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 pro-
file 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 sug-
gest 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 analy-
sis 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 sym-
spec 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 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.
"-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 stan-
dard-output. If this option is specified, annotated source for a file named path/filename is generated in
the file filename-ann. If the underlying file system 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 for-
mat 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 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 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 identi-
fied, 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 iso-
late 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 sup-
pressed.
"-n[symspec]"
"--time[=symspec]"
The -n option causes "gprof", in its call graph analysis, to only propagate times for symbols matching sym-
spec.
"-N[symspec]"
"--no-time[=symspec]"
The -n option causes "gprof", in its call graph analysis, not to propagate times for symbols matching sym-
spec.
"-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.
"-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 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 function_name"
The -e function option tells "gprof" to not print information about the function function_name (and its chil-
dren...) 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 func-
tion_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 exe-
cution of a function can be expressed by the total time for the function divided by the number of times the func-
tion is called. Thus the time propagated along the call graph arcs to the function's parents is directly propor-
tional 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 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.
RELATED
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 Documenta-
tion License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sec-
tions, 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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