SPROF(1)		       Linux User Manual		      SPROF(1)



NAME
       sprof - read and display shared object profiling data

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

DESCRIPTION
       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	 <son-
       ame>.profile in the current directory.

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

EXAMPLE
       The  following example demonstrates the use of sprof.  The example con-
       sists 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 writ-
       ten 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
       gprof(1), ldd(1), ld.so(8)

COLOPHON
       This  page  is  part of release 4.10 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)