Analyzing run-time behavior

Compiling the program for use with prof

The steps for compiling a program for timing profiling are basically the same as those described for lprof.

To arrange for timing and function call count data to be written to a data file at the end of execution, you must compile your source files with the -p (or -qp) option to profile a program with prof. Using the same example described previously:

$ cc -p -o travel travel.c misc.c

The same -p (or -qp) option is used to profile a C++ program:

$ CC -p -o travel travel.C misc.C

As noted earlier, if you compile and link your program in separate steps, you must specify -p when you link as well as when you compile:

   $ cc -p -c travel.c
   $ cc -p -c misc.c
   $ cc -p -o travel travel.o misc.o

Alternatively, if recompiling your program is not convenient, you can use fur to insert profiling code into your objects.

   $ fur -P prof.o -p all travel.o
   $ fur -P prof.o -p all misc.o
   $ cc -p -o travel travel.o misc.o

See ``Invoking prof'' for the options you must specify to use the profiler on a program with a name other than a.out.

As with lprof, you can gather data for parts of a program by only compiling the relevant source with the -p option. Note that you may still see timing information for functions defined in the "non-profiled" source, but no call count data will be produced.

   $ cc -p -c travel.c
   $ cc -c misc.c
   $ cc -p -o travel travel.o misc.o

In this case, no call count information will be produced for functions defined in misc.c but any timing signals caught while executing such functions will be reported.