gprof - display call graph profile data
gprof [options] [a.out [gmon.out...]] [shared_library
The gprof command produces an execution profile of C++, C, Pascal, and
FORTRAN programs. The effect of called routines is incorporated into
the profile of each caller. Profile data is taken from the call graph
profile file (gmon.out default) that is created by programs compiled
with the -G option of aCC, CC, cc, pc, and f77. That option also
links in versions of the library routines that are compiled for
profiling. The symbol table in the named object file (a.out default)
is read and correlated with the call graph profile file. If more than
one profile file is specified, gprof output shows the sum of the
profile information in the given profile files.
First, a flat profile is given, similar to that provided by prof (see
prof(1)). This listing gives the total execution times and call
counts for each function in the program, sorted by decreasing time.
Next, these times are propagated along the edges of the call graph.
gprof discovers all cycles in the call graph. All calls made into the
cycle share the time of that cycle. A second listing shows the
functions sorted according to the time they represent including the
time of their call graph descendants. Below each function entry is
shown its (direct) call graph children, and how their times are
propagated to this function. A similar display above the function
shows how the time of this function and the time of its descendants
are propagated to its (direct) call graph parents.
Cycles are also shown, with an entry for the cycle as a whole and a
listing of the members of the cycle, each with their contributions to
the time and call counts of the cycle.
Shared Library Profiling (32-bit only)
Support for gprof profiling of shared libraries is available on 32-bit
To profile shared libraries, set the environment variable LD_PROFILE
to the path of the shared library to be profiled. (See HP-UX Linker
and Libraries Online User's Guide for details.) Do not use the -G
option to compile programs for shared libraries profiling. Do not
link the executable gcrt0.o or mcrt0.o. This turns on profiling of
a.out, which is not compatible with profiling of shared libraries. You
can either profile your executable or a shared library, but not both.
At the termination of the program, a profile file with the name of the
shared library prepended to it is generated by a run-time library. To
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get the complete listing, provide the gprof command with names of the
shared library and the profile file for the shared library as
The gprof command recognizes the following options:
-a Suppress printing statically declared functions.
If this option is given, all relevant information
about the static function (such as time samples,
calls to other functions, and calls from other
functions) belongs to the function loaded just
before the static function in the a.out file.
-b Suppress printing a description of each field in
-e name Suppress printing the graph profile entry for
routine name and all its descendants (unless they
have other ancestors that are not suppressed).
More than one -e option can be given. Only one
name can be given with each -e option.
-E name Suppress printing the graph profile entry for
routine name (and its descendants) as -e above,
and also exclude the time spent in name (and its
descendants) from the total and percentage time
computations. -E mcount -E mcleanup is the
-f name Print only the graph profile entry of the
specified routine name and its descendants. More
than one -f option can be given. Only one name
can be given with each -f option.
-F name Print only the graph profile entry of the routine
name and its descendants (as -f above) and also
use only the times of the printed routines in
total time and percentage computations. More than
one -F option can be given. Only one name can be
given with each -F option. The -F option
overrides the -E option.
-s Produce a profile file gmon.sum that represents
the sum of the profile information in all
specified profile files. This summary profile
file can be given to subsequent executions of
gprof (probably also with a -s option) to
accumulate profile data across several runs of an
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-z Display routines that have zero usage (as
indicated by call counts and accumulated time).
The name of the file created by a profiled program is controlled by
the environment variable GPROFDIR. If GPROFDIR is not set, gmon.out
is produced in the current directory when the program terminates. If
GPROFDIR=string, string/pid.progname is produced, where progname
consists of argv with any path prefix removed, and pid is the
program's process ID. If GPROFDIR is set to a null string, no
profiling output is produced.
To profile libc.sl:
$ cat >>>> test.c
$ cc test.c -lc
$ ldd a.out
/usr/lib/libc.2 => /usr/lib/libc.2
/usr/lib/libdld.2 => /usr/lib/libdld.2
/usr/lib/libc.2 => /usr/lib/libc.2
$ export LD_PROFILE=/usr/lib/libc.2
$ unset LD_PROFILE
$ ls libc.2.profile
$ ll libc.2.profile
-rw-rw-r-- 1 user1 lang 606464 May 19 10:24 libc.2.profile
$ gprof /usr/lib/libc.2 libc.2.profile
Beware of quantization errors. The granularity of the sampling is
shown, but remains statistical at best. It is assumed 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 parents
of that function is directly proportional to the number of times that
arc is traversed.
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Parents that are not profiled have the time of their profiled children
propagated to them, but they appear to be spontaneously invoked in the
call graph listing, and do not have their time propagated further.
Similarly, signal catchers, even though profiled, 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() (see exit(2)) or return
normally, for the profiling information to be saved in the gmon.out
The following limitations exist for gprof shared library profiling:
+ Local, static, and hidden functions are not profiled.
+ Shared libraries built with -B symbolic are not profiled.
+ Any function calls made from library initializers are not
Set LD_PROFILE to the exact string with which you call shl_load. If
the library is implicitly loaded, LD_PROFILE must match the path
encoded in the a.out. You can find this value by running the ldd
command on the executable.
gprof cannot be used with dynamically linked executables (built with
ld -A in pre HP-UX 10.20 releases).
gprof was developed by the University of California, Berkeley.
a.out* Default object file.
gmon.out* Default dynamic call graph and
gmon.sum* Summarized dynamic call graph and
/usr/lib/gprof.callg* Call graph description.
/usr/lib/gprof.flat* Flat profile description.
/usr/lib/libgprof32.sl gprof 32-bit shared library
cc_bundled(1), prof(1), exit(2), profil(2), crt0(3), monitor(3C).
gprof: A Call Graph Execution Profiler; Graham, S.L., Kessler, P.B.,
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Proceedings of the SIGPLAN '82 Symposium on Compiler Construction;
SIGPLAN Notices; Vol. 17, No. 6, pp. 120-126, June 1982.
HP-UX Linker and Libraries Online User's Guide (See the ld +help
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