4. gprof Command Summary

After you have a profile data file `gmon.out', you can run gprof to interpret the information in it. The gprof program prints a flat profile and a call graph on standard output. Typically you would redirect the output of gprof into a file with `>'.

You run gprof like this:

gprof options [executable-file [profile-data-files...]] [> outfile]

Here square-brackets indicate optional arguments.

If you omit the executable file name, the file `a.out' is used. If you give no profile data file name, the file `gmon.out' is used. If any file is not in the proper format, or if the profile data file does not appear to belong to the executable file, an error message is printed.

You can give more than one profile data file by entering all their names after the executable file name; then the statistics in all the data files are summed together.

The order of these options does not matter.

4.1 Output Options		Controlling gprof's output style
4.2 Analysis Options		Controlling how gprof analyses its data
4.3 Miscellaneous Options
4.4 Deprecated Options		Options you no longer need to use, but which have been retained for compatibility
4.5 Symspecs		Specifying functions to include or exclude

4.1 Output 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. See section 4.5 Symspecs.

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. See section 5.4 The Annotated Source Listing.

-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. See section 5.1 The Flat Profile.

-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. See section 5.2 The Call Graph.

-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/filename' 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 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.

--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

--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.

4.2 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. 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. See section 6.1 Statistical Sampling Error.

-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.

4.3 Miscellaneous Options

-d[num]

--debug[=num]

The `-d num' option specifies debugging options. If num is not specified, enable all debugging. See section 9.3.1 Debugging gprof.

-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.

4.4 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.

Note that only one function can be specified with each -e, -E, -f or -F option. To specify more than one function, use multiple options. For example, this command:

gprof -e boring -f foo -f bar myprogram > gprof.output

lists in the call graph all functions that were reached from either foo or bar and were not reachable from boring.

4.5 Symspecs

Many of the output options allow functions to be included or excluded using symspecs (symbol specifications), which observe the following syntax:

filename_containing_a_dot | funcname_not_containing_a_dot | linenumber | ( [ any_filename ] `:' ( any_funcname | linenumber ) )

Here are some sample symspecs:

`main.c'

Selects everything in file `main.c'---the dot in the string tells gprof to interpret the string as a filename, rather than as a function name. To select a file whose name does not contain a dot, a trailing colon should be specified. For example, `odd:' is interpreted as the file named `odd'.

`main'

Selects all functions named `main'.

Note that there may be multiple instances of the same function name because some of the definitions may be local (i.e., static). Unless a function name is unique in a program, you must use the colon notation explained below to specify a function from a specific source file.

Sometimes, function names contain dots. In such cases, it is necessary to add a leading colon to the name. For example, `:.mul' selects function `.mul'.

In some object file formats, symbols have a leading underscore. gprof will normally not print these underscores. When you name a symbol in a symspec, you should type it exactly as gprof prints it in its output. For example, if the compiler produces a symbol `_main' from your main function, gprof still prints it as `main' in its output, so you should use `main' in symspecs.

`main.c:main'

Selects function `main' in file `main.c'.

`main.c:134'

Selects line 134 in file `main.c'.