lprof(1) lprof(1)
NAME
lprof - display line-by-line execution count profile data
SYNOPSIS
lprof [-p] [-s] [-x] [-I incdir] [-r srcfile] [-c cntfile] [-o prog] [-V]
lprof -m file1.cnt file2.cnt filen.cnt [-T] -d destfile.cnt
DESCRIPTION
lprof reports the execution characteristics of a program on a (source)
line by line basis. This is useful as a means to determine which and
how often portions of the code were executed.
lprof interprets a profile file (prog.cnt by default) produced by the
profiled program prog (a.out by default). prog creates a profile file
if it has been loaded with the -ql option of cc. The profile informa-
tion is computed for functions in a source file if the -ql option was
used when the source file was compiled.
A shared object may also be profiled by specifying -ql when the shared
object is created. When a dynamically linked executable is run, one
profile file is produced for each profiled shared object linked to the
executable. This feature is useful in building a single report cover-
ing multiple and disparate executions of a common library. For exam-
ple, if programs prog1 and prog2 both use library libx.a, running
these profiled programs will produce two profile files, prog1.cnt and
prog2.cnt, which cannot be combined. However, if libx is built as a
profiled shared object, libx.so, and prog1 and prog2 are built as pro-
filed dynamically linked executables, then running these programs with
the merge option will produce three profile files; one of them,
libx.so.cnt, will contain the libx profile information from both runs.
By default, lprof prints a listing of source files (the names of which
are stored in the symbol table of the executable file), with each line
preceded by its line number (in the source file) and the number of
times the line was executed.
OPTIONS
The following options may appear singly or be combined in any order:
-p Print listing, each line preceded by the line number and the
number of times it was executed (default). This option can be
used together with the -s option to print both the source listing
and summary information.
-s Print summary information of percentage of lines of code executed
per function.
-x Instead of printing the execution count numbers of each line,
print each line preceded by its line number and a [U] if the line
was not executed. If the line was executed, print only the line
number.
Page 1 Reliant UNIX 5.44 Printed 11/98
lprof(1) lprof(1)
-I incdir
Look for source or header files in the directory incdir in addi-
tion to the current directory and the standard place for #include
files (usually /usr/include). The user can specify more than one
directory by using multiple -I options.
-r srcfile
Instead of printing all source files, print only those files
named in -r options (to be used with the -p option only). The
user can specify multiple files with a single -r option.
-c cntfile
Use the file cntfile instead of prog.cnt as the input profile
file.
-o prog
Use the name of the program prog instead of the name used when
creating the profile file. Because the program name stored in the
profile file contains the relative path, this option is necessary
if the executable file or profile file has been moved.
-V Print, on standard error, the version number of lprof.
Merging Data Files
lprof can also be used to merge profile files. The -m option must be
accompanied by the -d option:
-m file1.cnt file2.cnt filen.cnt -d
destfile.cnt Merge the data files file1.cnt through filen.cnt by
summing the execution counts per line, so that data from several
runs can be accumulated. The result is written to destfile.cnt.
The data files must contain profiling data for the same prog (see
the -T option below).
-T Time stamp override. Normally, the time stamps of the executable
files being profiled are checked, and data files will not be
merged if the time stamps do not match. If -T is specified, this
check is skipped.
Controlling the run-time profiling environment
The environment variable PROFOPTS provides run-time control over pro-
filing. When a profiled program (or shared object) is about to ter-
minate, it examines the value of PROFOPTS to determine how the profil-
ing data are to be handled. A terminating shared object will honor
every PROFOPTS option except file=filename.
The environment variable PROFOPTS is a comma-separated list of options
interpreted by the program being profiled. If PROFOPTS is not defined
in the environment, then the default action is taken: The profiling
data are saved in a file (with the default name, prog.cnt) in the
Page 2 Reliant UNIX 5.44 Printed 11/98
lprof(1) lprof(1)
current directory. If PROFOPTS is set to the null string, no profiling
data are saved. The following are the available options:
msg=[y|n]
If msg=y is specified, a message stating that profile data are
being saved is printed to stderr. If msg=n is specified, only the
profiling error messages are printed. The default is msg=y.
merge=[y|n]
If merge=y is specified, the data files will be merged after suc-
cessive runs. If merge=n is specified, the data files are not
merged after successive runs, and the data file is overwritten
after each execution. The merge will fail if the program has been
recompiled, and the data file will be left in TMPDIR. The default
is merge=n.
pid=[y|n]
If pid=y is specified, the name of the data file will include the
process ID of the profiled program. Inclusion of the process ID
allows for the creation of different data files for programs cal-
ling fork. If pid=n is specified, the default name is used. The
default is pid=n. For lprof to generate its profiling report, the
-c option must be specified with lprof otherwise the default will
fail.
dir=dirname
The data file is placed in the directory dirname if this option
is specified. Otherwise, the data file is created in the direc-
tory that is current at the end of execution.
file=filename
filename is used as the name of the data file in dir created by
the profiled program if this option is specified. Otherwise, the
default name is used. For lprof to generate its profiling report,
the -c option must be specified with lprof if the file option has
been used at execution time; otherwise the default will fail.
NOTES
For the -m option, if destfile.cnt exists, its previous contents are
destroyed.
Optimized code cannot be profiled; if both optimization and line pro-
filing are requested, profiling has precedence.
Programs that modify argv[0] are not operable under lprof.
Different parts of one line of a source file may be executed different
numbers of times (for example, the for loop below); the count corre-
sponds to the first part of the line.
Page 3 Reliant UNIX 5.44 Printed 11/98
lprof(1) lprof(1)
In the following example line 5 with the for loop has three parts:
main()
1 [2] {
int j;
1 [5] for (j = 0; j > 5; j++)
5 [6] sub(j);
1 [8] }
sub(a)
int a;
5 [12] {
5 [13] printf(a is %d\n, a);
5 [14] }
The number for the line refers to the initialization (j = 0).
FILES
prog.cnt Profile data
TMPDIR Usually /var/tmp but can be redefined by setting the
environment variable TMPDIR.
SEE ALSO
cc(1), fork(2), tmpnam(3S).
Page 4 Reliant UNIX 5.44 Printed 11/98