gprof
display call graph profile data
see also :
cc
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 ]
[--external-symbol-table=name]
[ image-file ] [ profile-file ... ]
add an example, a script, a trick and tips
examples
source
gprof ./gabble gmon.out > gabble.gproffed.txt
/big/common/gprof2dot.py -s gabble.gproffed.txt >
gabble.gprof.dot
/big/common/gprof2dot.py -s gabble.gproffed.txt >
gabble.gprof.dot
dot -Tpdf gabble.gprof.dot -ogabble.gprof.pdf
kpdf gabble.gprof.pdf
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.
If you use gcc
2.95.x or 3.0 to compile your binaries, you may need to add
the -fprofile-arcs to the compile command
line in order for the call graphs to be properly stored in
gmon.out.
"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 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.
"-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 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).
"-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
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
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. 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.
"-m
num"
"--min-count=num"
This option affects execution
count output only. Symbols that are executed less than
num times are suppressed.
"-nsymspec"
"--time=symspec"
The -n option
causes "gprof", in its call graph
analysis, to only propagate times for symbols matching
symspec.
"-Nsymspec"
"--no-time=symspec"
The -n option
causes "gprof", in its call graph
analysis, not to propagate times for symbols matching
symspec.
"-Sfilename"
"--external-symbol-table=filename"
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.
"-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 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.
copyright
Copyright (c) 1988, 1992, 1997, 1998, 1999, 2000, 2001, 2003,
2007, 2008, 2009 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 1.3 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".
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 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
cc ,
prof, 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.