NAME | SYNOPSIS | DESCRIPTION | OPTIONS | CONFORMING TO | EXAMPLE | SEE ALSO | COLOPHON

SPROF(1)                      Linux User Manual                     SPROF(1)

NAME         top

       sprof - read and display shared object profiling data

SYNOPSIS         top

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

DESCRIPTION         top

       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.

OPTIONS         top

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

       -c, --call-pairs
              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.

       -p, --flat-profile
              Generate a flat profile of all of the functions in the
              monitored object, with counts and ticks.

       -q, --graph
              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.

       --usage
              Display a short usage message and exit.

       -V, --version
              Display the program version and exit.

CONFORMING TO         top

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

EXAMPLE         top

       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);

           int
           main(int argc, char *argv[])
           {
               x1();
               x2();
               exit(EXIT_SUCCESS);
           }

       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>

           void
           consumeCpu1(int lim)
           {
               int j;

               for (j = 0; j < lim; j++)
                getppid();
           }

           void
           x1(void) {
               int j;

               for (j = 0; j < 100; j++)
                consumeCpu1(200000);
           }

           void
           consumeCpu2(int lim)
           {
               int j;

               for (j = 0; j < lim; j++)
                getppid();
           }

           void
           x2(void)
           {
               int j;

               for (j = 0; j < 1000; j++)
                consumeCpu2(10000);
           }

       Now we construct the shared object with the real name
       libdemo.so.1.0.1, and the soname libdemo.so.1:

           $ cc -g -fPIC -shared -Wl,-soname,libdemo.so.1 \
                   -o libdemo.so.1.0.1 libdemo.c

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

           $ ln -sf libdemo.so.1.0.1 libdemo.so.1
           $ ln -sf libdemo.so.1 libdemo.so

       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
                linux-vdso.so.1 =>  (0x00007fff86d66000)
                libdemo.so.1 => not found
                libc.so.6 => /lib64/libc.so.6 (0x00007fd4dc138000)
                /lib64/ld-linux-x86-64.so.2 (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 LD_PROFILE=libdemo.so.1

       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
           $ mkdir -p $LD_PROFILE_OUTPUT

       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:

           $ rm -f $LD_PROFILE_OUTPUT/$LD_PROFILE.profile

       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
           libdemo.so.1.profile

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

           $ sprof -p libdemo.so.1 $LD_PROFILE_OUTPUT/libdemo.so.1.profile
           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 libdemo.so.1 $LD_PROFILE_OUTPUT/libdemo.so.1.profile

           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 libdemo.so.1 $LD_PROFILE_OUTPUT/libdemo.so.1.profile
           <UNKNOWN>                  x1                                 1
           x1                         consumeCpu1                      100
           <UNKNOWN>                  x2                                 1
           x2                         consumeCpu2                     1000

SEE ALSO         top

       gprof(1), ldd(1), ld.so(8)

COLOPHON         top

       This page is part of release 4.12 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

Linux                            2015-08-08                         SPROF(1)

Pages that refer to this page: ldd(1)profil(3)ld.so(8)