GPROF(1)

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version 2.47 · 33 versions
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✨ GPROF(1) ✨

okay so bestie, welcome to the GNU gprof manual page — yes the whole thing, we're doing this, no skimming, no cap 💖

NAME 💖

gprof — display call graph profile data 🦋

SYNOPSIS 🌸

gprof [ -[abcDhilLrsTvwxyz] ] [ -[ABCeEfFJnNOpPqQRStZ][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 ] [ --inline-file-names ]
 [ --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 ... ]

DESCRIPTION 🫶

gprof makes an execution profile of your C, Pascal, or Fortran77 programs. and here's the tea 🍵 — the effect of called routines gets incorporated into the profile of each caller. so like, everybody shares the blame, it's giving group project energy.

the profile data comes from the call graph profile file (gmon.out by default), which gets created by programs that are compiled with the -pg option of cc, pc, and f77. and that same -pg option also links in versions of the library routines that are compiled for profiling. package deal, bestie.

Gprof reads the given object file (default is a.out, iconic) and establishes the relation between its symbol table and the call graph profile from gmon.out. and if you specify more than one profile file? the gprof output shows the sum of the profile info in the given profile files. math girlies rise 💅

then gprof calculates how much time got spent in each routine. next, those times get propagated along the edges of the call graph. cycles get discovered, and calls into a cycle are made to share the time of the cycle. it's all connected, iykyk 🔥

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 literally just want to know which functions burn most of the cycles, it is stated concisely here. quick and to the point, we love that.
  • the call graph shows, for each function, which functions called it, which other functions it called, and how many times. there's 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. detective work fr 🔍
  • 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. it's giving receipts for every line 🌈

OPTIONS 💅

these options specify which of several output formats gprof should produce. pick your fighter.

many of these options take an optional symspec to specify functions to be included or excluded. and you can specify these options multiple times with different symspecs, to include or exclude sets of symbols. so flexible, we stan.

heads up bestie: specifying any of these options overrides the default (-p -q), which prints a flat profile and call graph analysis for all functions. don't say i didn't warn you 😭
  • -A[symspec], --annotated-source[=symspec] — the -A option makes gprof 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. useful if you intend to print out the output, or are just tired of seeing the blurbs. we've all been there 🙈
  • -B — the -B option makes gprof print the call graph analysis.
  • -C[symspec], --exec-counts[=symspec] — the -C option makes gprof print a tally of functions and the number of times each was called. if symspec is specified, print tally only for matching symbols.
    • bonus: 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. slay ✨
  • -i, --file-info — the -i option makes gprof display summary info about the profile data file(s) and then exit. the number of histogram, call graph, and basic-block count records is displayed. and then it's gone, bye 👋
  • -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 info. used mostly for annotated source output. 🦋
  • -J[symspec], --no-annotated-source[=symspec] — the -J option makes gprof not print annotated source code. if symspec is specified, gprof prints annotated source, but excludes matching symbols. the way it flips the meaning is lowkey wild.
  • -L, --print-path — normally, source filenames are printed with the path component suppressed. the -L option makes gprof 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. full address reveal 🏠
  • -p[symspec], --flat-profile[=symspec] — the -p option makes gprof print a flat profile. if symspec is specified, print flat profile only for matching symbols.
  • -P[symspec], --no-flat-profile[=symspec] — the -P option makes gprof 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 makes gprof print the call graph analysis. if symspec is specified, print call graph only for matching symbols and their children. keeping it in the family fr 👑
  • -Q[symspec], --no-graph[=symspec] — the -Q option makes gprof 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 makes the num most active source lines in each source file get listed when source annotation is enabled. the default is 10. top ten countdown, let's go 🎉
  • -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. and 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). safety first bestie 💜
  • -Z[symspec], --no-exec-counts[=symspec] — the -Z option makes gprof not 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 makes gprof 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. not our problem, respectfully 🙈
  • -R map_file, --file-ordering map_file — the --file-ordering option makes gprof 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. seriously, do it.
    • 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. look:
        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. copy that exactly bestie, don't freestyle it 💅
  • -T, --traditional — the -T option makes gprof print its output in "traditional" BSD style. vintage aesthetic, we love a throwback 🎀
  • -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. niche but important.
  • -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. the way it repeats itself is giving echo 🗣️
  • --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. read the room (and your compiler) bestie 🧚

Analysis Options 🌈

  • -a, --no-static — the -a option makes gprof 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. it's giving "you didn't see anything" 🤫
  • -c, --static-call-graph — okay so this one is a little genius. -c makes the call graph get beefed up by a heuristic that goes digging through the text space of the object file and sniffs out function calls hiding inside the binary machine code. Why does that matter? Because normal call graph records only get made when a function actually gets entered, so this option catches the children that could have been called but never were. It also spots calls to functions that weren't compiled with profiling on — but only if there are symbol table entries for them, so no entries, no luck. Calls to dynamic library routines? Typically not found by this option, sorry bestie. And any parent or child found by this heuristic shows up in the call graph with call counts of 0. 💅
  • -D, --ignore-non-functions — makes gprof straight up ignore symbols that aren't known to be functions. On systems where it's supported (Solaris and HPUX for example) this gives you more accurate profile data. Slay. ✨
  • -k from/to — this one lets you delete arcs from the call graph. Any arc from symbols matching symspec from to those matching symspec to? Gone. Poof. 🫶
  • -l, --line — turns on line-by-line profiling, which charges histogram hits to individual source code lines instead of whole functions. Important caveat though: this feature only works with programs compiled by older versions of the gcc compiler. Newer gcc versions are designed to work with the gcov tool instead. If the program was compiled with basic-block counting enabled, -l will also tell you how many times each line of code was executed. And yes, line-by-line profiling can genuinely help isolate where in a big function your program is burning time — but it also significantly increases the running time of gprof and magnifies statistical inaccuracies. So like, use it with your eyes open. 😭
  • --inline-file-names — prints the source file after each symbol, in both the flat profile and the call graph. And if you use it together with the -L option, you get the full path to the file. 🎀
  • -m num, --min-count=num — this one only touches execution count output. Symbols executed fewer than num times get suppressed. Quietly removed. Not invited to the party. 🙈
  • -n symspec, --time=symspec — in its call graph analysis, this causes gprof 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.
  • -S filename, --external-symbol-table=filename — makes gprof read an external symbol table file — like /proc/kallsyms — instead of reading the symbol table out of the given object file (the default is a.out). Super useful for profiling kernel modules, iykyk. 👑
  • -z, --display-unused-functions — give -z and gprof will mention all the functions in the flat profile, even the ones that were never called and had zero time spent in them. Chef's kiss when you pair it with the -c option, because then you can find out exactly which routines were never called. Detective mode fr fr. 🔍

🌈 Miscellaneous Options 🌈

  • -d[num], --debug[=num] — specifies debugging options. And if num isn't specified at all? All debugging gets enabled. Go big or go home. 💀
  • -h, --help — prints the command line usage. Your classic "help me please" button. 💖
  • -O name, --file-format=name — selects the format of the profile data files. The recognized formats are auto (which is the default), bsd, 4.4bsd, magic, and prof (not yet supported). ⭐
  • -s, --sum — makes gprof summarize all the info in the profile data files it read in, and write out a profile data file called gmon.sum, which holds all the information from the profile data files that gprof read in. Plot twist: gmon.sum may itself be one of the specified input files — and the effect of that is to merge the data from the other input files into gmon.sum. Eventually you can run gprof again without -s to analyze the cumulative data sitting in gmon.sum. 🦋
  • -v, --version — prints the current version number and then exits. Short, sweet, iconic. 👑

🚫 Deprecated Options 🚫

Okay so these options have been replaced with newer versions that use symspecs. They're still here, but like… they're the older sibling that got replaced by the cooler younger sibling. 💅
  • -e function_name — 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]. You can give more than one -e option, but only one function_name may be indicated with each -e option. 🫶
  • -E function_name — works like the -e option, but the 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 — 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 — 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. And heads up: 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 it remains statistical at best. And here's the assumption we're rolling with: 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. So 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. That's the math, that's the vibe. 😭

Parents that are not themselves profiled will have the time of their profiled children propagated to them — but they'll appear to be spontaneously invoked in the call graph listing, and their time won't be propagated any further. Similarly, signal catchers, even though they're profiled, will appear to be spontaneous (although for more obscure reasons, ngl). 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. 💀

And the big one, bestie:

The profiled program must call exit(2) or return normally for the profiling information to be saved in the gmon.out file. No exit, no data. Periodt.

👀 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 Construction, SIGPLAN Notices, Vol. 17, No 6, pp. 120-126, June 1982.

Copyright (c) 1988-2026 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".

And that's the whole page, bestie!! 🫶 This was binutils-2.47, dated 2026-08-11, and the page itself is GPROF(1). Go forth and profile something iconic. 💖✨

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