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feedback(1)							  feedback(1)



NAME

  feedback - Generate an optimization feedback file using pixie	and prof

SYNOPSIS

  feedback [prof-options] [-o feedback-file] [-v] objfile [objfile-arguments]

OPTIONS

  prof-options
      The feedback command accepts the following prof(1) options and any
      unambiguous abbreviations: -asm, -clock megahertz, -{e|E}xclude
      procedure_name, -feedback	filename, -heavy, -invocations,	-lines,
      -merge filename, -numbers, -{o|O}nly procedure_name, -procedures,	-quit
      n, -testcoverage,	-truecycles [0,1,2], -zero.

      The feedback command ignores all other options in	order to provide com-
      patiblility with older versions of the feedback command.	An option
      argument following an option not recognized by this or older versions
      of the feedback command will be treated as the objfile argument.

  -o feedback-file
      Specifies	the name of the	feedback file. This can	also be	specified by
      the -feedback option of prof.  You should	use only one of	these options
      to specify a feedback file, not both.

  -v  Causes the pixie,	application, and prof commands to be printed as	they
      are invoked.

OPERANDS

  objfile
      Specifies	the executable of the application for which a feedback file
      is to be generated.  A pixie-instrumented	version	of this	executable
      will be executed with the	current	working	directory and environment
      variables.

  objfile-arguments
      The feedback file	that is	generated will reflect the behavior of one
      execution	of the instrumented objfile. Specify the arguments that	will
      cause the	behavior that you want to have optimized when the compiler
      uses the feedback	file.

DESCRIPTION

  The feedback command invokes pixie to	add profiling code to an object	file.
  The object file generated by pixie is	executed to obtain profiling informa-
  tion.	 The feedback command then invokes prof	to analyze the profiling
  information.

  If the output	of objfile needs to be redirected, but not the output of the
  feedback utility, the	redirection characters need to have sh(1) syntax and
  be within quotes. If objfile is multi-threaded, the LD_LIBRARY_PATH
  environment variable needs to	include	the current working directory.





EXAMPLES

   1.  Send the	profiling information to the standard output:
	    $ feedback myprog

   2.  Write a binary formatted	performance profile to the file
       myprog.feedback,	which then helps a subsequent recompilation optimize
       the program:
	    $ feedback -feedback myprog.feedback myprog
	    $ cc -O -feedback myprog.feedback -o myprog	myprog.c



FILES

  ./myprog.pixie
      Object with profiling code. Generated by pixie.

  ./myprog.Addrs
      Basic block addresses.  Generated	by pixie.

  ./myprog.Counts
      Basic block counts.  Generated by	myprog.pixie.

  Note:	Run pixie and prof independently if alternative	names are needed.

SEE ALSO

  cc(1), pixie(5), prof(1)