"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
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
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
These options specify which of several output formats "gprof" should
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
Specifying any of these options overrides the default (-p -q), which
prints a flat profile and call graph analysis for all functions.
The -A option causes "gprof" to print annotated source code. If
symspec is specified, print output only for matching symbols.
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.
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.
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.
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
The -J option causes "gprof" not to print annotated source code.
If symspec is specified, "gprof" prints annotated source, but
excludes matching symbols.
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.
The -p option causes "gprof" to print a flat profile. If symspec
is specified, print flat profile only for matching symbols.
The -P option causes "gprof" to suppress printing a flat profile.
If symspec is specified, "gprof" prints a flat profile, but
excludes matching symbols.
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.
The -Q option causes "gprof" to suppress printing the call graph.
If symspec is specified, "gprof" prints a call graph, but
excludes matching symbols.
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.
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 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).
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.
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
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".
The -T option causes "gprof" to print its output in "traditional"
Sets width of output lines to width. Currently only used when
printing the function index at the bottom of the call graph.
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.
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.
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.
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 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.
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
The -k option allows you to delete from the call graph any arcs
from symbols matching symspec from to those matching symspec to.
The -l option enables line-by-line profiling, which causes
histogram hits to be charged to individual source code lines,
instead of functions. This feature only works with programs
compiled by older versions of the "gcc" compiler. Newer versions
of "gcc" are designed to work with the "gcov" tool instead.
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.
This option causes "gprof" to print the source file after each
symbol in both the flat profile and the call graph. The full path
to the file is printed if used with the -L option.
This option affects execution count output only. Symbols that
are executed less than num times are suppressed.
The -n option causes "gprof", in its call graph analysis, to only
propagate times for symbols matching symspec.
The -n option causes "gprof", in its call graph analysis, not to
propagate times for symbols matching symspec.
The -S option causes "gprof" to read an external symbol table
file, such as /proc/kallsyms, rather than read the symbol table
from the given object file (the default is "a.out"). This is
useful for profiling kernel modules.
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.
The -d num option specifies debugging options. If num is not
specified, enable all debugging.
The -h option prints command line usage.
Selects the format of the profile data files. Recognized formats
are auto (the default), bsd, 4.4bsd, magic, and prof (not yet
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.
The -v flag causes "gprof" to print the current version number,
and then exit.
These options have been replaced with newer versions that use
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.
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.
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.
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.
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 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.
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
Copyright (c) 1988-2016 Free Software Foundation, Inc.
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