feedback(1)feedback(1)NAMEfeedback - Generate an optimization feedback file using pixie and prof
SYNOPSISfeedback [prof-options] [-o feedback-file] [-v] objfile [objfile-argu‐
ments]
OPTIONS
The feedback command accepts the following prof(1) options and any
unambiguous abbreviations: -asm, -clock megahertz, -{e|E}xclude proce‐
dure_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 pro‐
vide compatiblility 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. 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. Causes the pixie, application, and prof commands to
be printed as they are invoked.
OPERANDS
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. The feedback file that is generated will reflect the behav‐
ior 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 profil‐
ing information. 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 work‐
ing directory.
EXAMPLES
Send the profiling information to the standard output: $ feedback
myprog 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 -feed‐
back myprog.feedback -o myprog myprog.c
FILES
Object with profiling code. Generated by pixie. Basic block addresses.
Generated by pixie. Basic block counts. Generated by myprog.pixie.
Note: Run pixie and prof independently if alternative names are needed.
SEE ALSOcc(1), pixie(5), prof(1)feedback(1)