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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 pro-
grams. 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 profil-
ing. "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 func-
tion, 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 func-
tion. This can suggest places where you might try to eliminate func-
tion 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, speci-
fying the -l option, along with -C, will cause basic-block execu-
tion 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 sup-
pressed. 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/file-
name is generated in 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 order-
ing 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 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 func-
tion name to object file mappings. The format of the file is simi-
lar 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 sim-
ilar 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. Differ-
ent compilers have different mangling styles. The optional deman-
gling style argument can be used to choose an appropriate deman-
gling 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 profil-
ing enabled are also identified, but only if symbol table entries
are present for them. Calls to dynamic library routines are typi-
cally 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 his-
togram hits to be charged to individual source code lines, instead
of functions. If the program was compiled with basic-block count-
ing 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.
"-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 spec-
ified, 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 sup-
ported).
"-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 pro-
file 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 sym-
specs.
"-e function_name"
The -e function option tells "gprof" to not print information about
the function 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 func-
tion_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 func-
tion_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 func-
tion_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 children propagated to them, but they will appear to be spon-
taneously invoked in the call graph listing, and will not have their
time propagated further. Similarly, signal catchers, even though pro-
filed, will appear to be spontaneous (although for more obscure rea-
sons). 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.
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 Con-
struction, SIGPLAN Notices, Vol. 17, No 6, pp. 120-126, June 1982.
COPYRIGHT
Copyright (C) 1988, 92, 97, 98, 99, 2000, 2001 Free Software Founda-
tion, 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".
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