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sprof(1) General Commands Manual sprof(1)


sprof - read and display shared object profiling data


sprof [option]... shared-object-path [profile-data-path]


The sprof command displays a profiling summary for the shared object (shared library) specified as its first command-line argument. The profiling summary is created using previously generated profiling data in the (optional) second command-line argument. If the profiling data pathname is omitted, then sprof will attempt to deduce it using the soname of the shared object, looking for a file with the name <soname>.profile in the current directory.


The following command-line options specify the profile output to be produced:

Print a list of pairs of call paths for the interfaces exported by the shared object, along with the number of times each path is used.
Generate a flat profile of all of the functions in the monitored object, with counts and ticks.
Generate a call graph.

If none of the above options is specified, then the default behavior is to display a flat profile and a call graph.

The following additional command-line options are available:

-?, --help
Display a summary of command-line options and arguments and exit.
Display a short usage message and exit.
Display the program version and exit.


The sprof command is a GNU extension, not present in POSIX.1.


The following example demonstrates the use of sprof. The example consists of a main program that calls two functions in a shared object. First, the code of the main program:

$ cat prog.c
#include <stdlib.h>
void x1(void);
void x2(void);
main(int argc, char *argv[])


The functions x1() and x2() are defined in the following source file that is used to construct the shared object:

$ cat libdemo.c
#include <unistd.h>
consumeCpu1(int lim)

for (unsigned int j = 0; j < lim; j++) getppid(); } void x1(void) {
for (unsigned int j = 0; j < 100; j++) consumeCpu1(200000); } void consumeCpu2(int lim) {
for (unsigned int j = 0; j < lim; j++) getppid(); } void x2(void) {
for (unsigned int j = 0; j < 1000; j++) consumeCpu2(10000); }

Now we construct the shared object with the real name, and the soname

$ cc -g -fPIC -shared -Wl,-soname, \

-o libdemo.c

Then we construct symbolic links for the library soname and the library linker name:

$ ln -sf
$ ln -sf

Next, we compile the main program, linking it against the shared object, and then list the dynamic dependencies of the program:

$ cc -g -o prog prog.c -L. -ldemo
$ ldd prog =>  (0x00007fff86d66000) => not found => /lib64/ (0x00007fd4dc138000)
	/lib64/ (0x00007fd4dc51f000)

In order to get profiling information for the shared object, we define the environment variable LD_PROFILE with the soname of the library:

$ export

We then define the environment variable LD_PROFILE_OUTPUT with the pathname of the directory where profile output should be written, and create that directory if it does not exist already:

$ export LD_PROFILE_OUTPUT=$(pwd)/prof_data

LD_PROFILE causes profiling output to be appended to the output file if it already exists, so we ensure that there is no preexisting profiling data:


We then run the program to produce the profiling output, which is written to a file in the directory specified in LD_PROFILE_OUTPUT:

$ LD_LIBRARY_PATH=. ./prog
$ ls prof_data

We then use the sprof -p option to generate a flat profile with counts and ticks:

$ sprof -p $LD_PROFILE_OUTPUT/
Flat profile:
Each sample counts as 0.01 seconds.

% cumulative self self total
time seconds seconds calls us/call us/call name
60.00 0.06 0.06 100 600.00 consumeCpu1
40.00 0.10 0.04 1000 40.00 consumeCpu2
0.00 0.10 0.00 1 0.00 x1
0.00 0.10 0.00 1 0.00 x2

The sprof -q option generates a call graph:

$ sprof -q $LD_PROFILE_OUTPUT/
index % time    self  children    called     name

0.00 0.00 100/100 x1 [1] [0] 100.0 0.00 0.00 100 consumeCpu1 [0] -----------------------------------------------
0.00 0.00 1/1 <UNKNOWN> [1] 0.0 0.00 0.00 1 x1 [1]
0.00 0.00 100/100 consumeCpu1 [0] -----------------------------------------------
0.00 0.00 1000/1000 x2 [3] [2] 0.0 0.00 0.00 1000 consumeCpu2 [2] -----------------------------------------------
0.00 0.00 1/1 <UNKNOWN> [3] 0.0 0.00 0.00 1 x2 [3]
0.00 0.00 1000/1000 consumeCpu2 [2] -----------------------------------------------

Above and below, the "<UNKNOWN>" strings represent identifiers that are outside of the profiled object (in this example, these are instances of main()).

The sprof -c option generates a list of call pairs and the number of their occurrences:

$ sprof -c $LD_PROFILE_OUTPUT/
<UNKNOWN>                  x1                                 1
x1                         consumeCpu1                      100
<UNKNOWN>                  x2                                 1
x2                         consumeCpu2                     1000


gprof(1), ldd(1),

2023-01-07 Linux man-pages 6.03