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MAN page from RedHat EL 6 toolchain-armiwmmx-2012-2012.12.1-oselas.2.2.x86_64.rpm

GPROF

Section: GNU (1)
Updated: 2011-06-27
Index 

NAME

gprof - display call graph profile data 

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 ... ] 

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 programsthat are compiled with the -pg option of"cc", "pc", and "f77".The -pg option also links in versions of the library routinesthat are compiled for profiling. "Gprof" reads the given object file (the default is "a.out") and establishes the relation betweenits 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 timeof 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 knowwhich functions burn most of the cycles, it is stated concisely here.

The call graph shows, for each function, which functions called it, whichother functions it called, and how many times. There is also an estimateof how much time was spent in the subroutines of each function. This cansuggest places where you might try to eliminate function calls that use alot of time.

The annotated source listing is a copy of the program'ssource code, labeled with the number of times each line of theprogram was executed. 

OPTIONS

These options specify which of several output formats"gprof" should produce.

Many of these options take an optional symspec to specifyfunctions to be included or excluded. These options can bespecified multiple times, with different symspecs, to includeor exclude sets of symbols.

Specifying any of these options overrides the default (-p -q),which prints a flat profile and call graph analysisfor 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 theverbose blurbs that try to explain the meaning of all of the fields inthe tables. This is useful if you intend to print out the output, orare tired of seeing the blurbs.
-C[symspec]
--exec-counts[=symspec]
The -C option causes "gprof" toprint 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, specifyingthe -l option, along with -C, will cause basic-blockexecution counts to be tallied and displayed.

-i
--file-info
The -i option causes "gprof" to display summary informationabout 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 inwhich to find source files. Environment variable GPROF_PATHcan 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 toprint 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 pathcomponent suppressed. The -L option causes "gprof"to print the full pathname ofsource filenames, which is determinedfrom symbolic debugging information in the image fileand is relative to the directory in which the compilerwas 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 symbolsand their children.
-Q[symspec]
--no-graph[=symspec]
The -Q option causes "gprof" to suppress printing thecall 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 ineach source file to be listed when source annotation is enabled. Thedefault is 10.
-y
--separate-files
This option affects annotated source output only.Normally, "gprof" prints annotated source filesto standard-output. If this option is specified,annotated source for a file named path/filenameis generated in the file filename-ann. If the underlyingfile system would truncate filename-ann so that itoverwrites the original filename, "gprof" generatesannotated source in the file filename.ann instead (if theoriginal file name has an extension, that extension is replacedwith .ann).
-Z[symspec]
--no-exec-counts[=symspec]
The -Z option causes "gprof" not toprint 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 asuggested function ordering for the program based on profiling data.This option suggests an ordering which may improve paging, tlb andcache behavior for the program on systems which support arbitraryordering of functions in an executable.

The exact details of how to force the linker to place functionsin a particular order is system dependent and out of the scope of thismanual.

-R map_file
--file-ordering map_file
The --file-ordering option causes "gprof" to print asuggested .o link line ordering for the program based on profiling data.This option suggests an ordering which may improve paging, tlb andcache behavior for the program on systems which do not support arbitraryordering 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 providesfunction name to object file mappings. The format of the file is similar tothe 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 bottomof the call graph.
-x
--all-lines
This option affects annotated source output only.By default, only the lines at the beginning of a basic-blockare annotated. If this option is specified, every line ina basic-block is annotated by repeating the annotation for thefirst line. This behavior is similar to "tcov"'s -a.
--demangle[=style]
--no-demangle
These options control whether C++ symbol names should be demangled whenprinting 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 ofstatically declared (private) functions. (These are functions whosenames are not listed as global, and which are not visible outside thefile/function/block where they were defined.) Time spent in thesefunctions, calls to/from them, etc., will all be attributed to thefunction 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 beaugmented by a heuristic which examines the text space of the objectfile and identifies function calls in the binary machine code.Since normal call graph records are only generated when functions areentered, this option identifies children that could have been called,but never were. Calls to functions that were not compiled withprofiling enabled are also identified, but only if symbol tableentries are present for them.Calls to dynamic library routines are typically not foundby this option.Parents or children identified via this heuristicare indicated in the call graph with call counts of 0.
-D
--ignore-non-functions
The -D option causes "gprof" to ignore symbols whichare not known to be functions. This option will give more accurateprofile data on systems where it is supported (Solaris and HPUX forexample).
-k from/to
The -k option allows you to delete from the call graph any arcs fromsymbols matching symspec from to those matching symspec to.
-l
--line
The -l option enables line-by-line profiling, which causeshistogram hits to be charged to individual source code lines,instead of functions. This feature only works with programs compiledby 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 ofcode was executed.While line-by-line profiling can help isolate where in a large functiona program is spending its time, it also significantly increasesthe running time of "gprof", and magnifies statisticalinaccuracies.

-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 tablefile, 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 allfunctions in the flat profile, even those that were never called, andthat 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 areauto (the default), bsd, 4.4bsd, magic, andprof (not yet supported).
-s
--sum
The -s option causes "gprof" to summarize the informationin the profile data files it read in, and write out a profile datafile called gmon.sum, which contains all the information fromthe profile data files that "gprof" read in. The file gmon.summay be one of the specified input files; the effect of this is tomerge the data in the other input files into gmon.sum.

Eventually you can run "gprof" again without -s to analyze thecumulative data in the file gmon.sum.

-v
--version
The -v flag causes "gprof" to print the current versionnumber, 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 printinformation about the function function_name (and itschildren...) in the call graph. The function will still be listedas a child of any functions that call it, but its index number will beshown as [not printed]. More than one -e option may begiven; only one function_name may be indicated with each -eoption.
-E function_name
The "-E function" option works like the "-e" option, buttime spent in the function (and children who were not called fromanywhere else), will not be used to compute the percentages-of-time forthe call graph. More than one -E option may be given; only onefunction_name may be indicated with each -E option.
-f function_name
The -f function option causes "gprof" to limit thecall graph to the function function_name and its children (andtheir children...). More than one -f option may be given;only one function_name may be indicated with each -foption.
-F function_name
The -F function option works like the "-f" option, butonly time spent in the function and its children (and theirchildren...) will be used to determine total-time andpercentages-of-time for the call graph. More than one -F optionmay be given; only one function_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 remainsstatistical at best.We assume that the time for each execution of a functioncan be expressed by the total time for the function dividedby the number of times the function is called.Thus the time propagated along the call graph arcs to the function'sparents is directly proportional to the number of times thatarc is traversed.

Parents that are not themselves profiled will have the time oftheir profiled children propagated to them, but they will appearto be spontaneously invoked in the call graph listing, and willnot have their time propagated further.Similarly, signal catchers, even though profiled, will appearto be spontaneous (although for more obscure reasons).Any profiled children of signal catchers should have their timespropagated properly, unless the signal catcher was invoked duringthe 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 savedin 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 Construction,SIGPLAN Notices, Vol. 17, No 6, pp. 120-126, June 1982. 

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 documentunder the terms of the GNU Free Documentation License, Version 1.3or any later version published by the Free Software Foundation;with no Invariant Sections, with no Front-Cover Texts, and with noBack-Cover Texts. A copy of the license is included in thesection entitled ``GNU Free Documentation License''.


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
Analysis Options
Miscellaneous Options
Deprecated Options
FILES
BUGS
SEE ALSO
COPYRIGHT

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