SIMPLE SOLUTIONS

SPROF(1) - man page online | user commands

Read and display shared object profiling data.

Chapter
2015-08-08
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 pre‐ viously 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 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 consists of a main pro‐ gram 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 con‐ struct 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 direc‐ tory 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 gprof(1), ldd(1), ld.so(8)
COLOPHON This page is part of release 4.04 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 http://www.kernel.org/doc/man-pages/.
Linux 2015-08-08 SPROF(1)
This manual Reference Other manuals
sprof(1) referred by ld.so(8) | ldd(1) | profil(3)
refer to i686-linux-gnu-gprof(1) | ld.so(8) | ldd(1)