cord(1) 						      General Commands Manual							   cord(1)

NAME

       cord - Rearrange procedures in an executable file to facilitate better cache mapping

SYNOPSIS

       cord [-vV] [-o outfile] [-f] [-c cachesize] [-p maxphases] obj-file reorder-file

OPTIONS

       The cord command accepts the following options: Prints verbose information. This includes listing those procedures that are considered part
       of other procedures and that cannot be rearranged (that is, assembler procedures that may contain relative  branches  to  other	procedures
       instead	of  relocatable  branches).  The listing also lists those procedures in the flipped area (if any) and a mapping of old location to
       new.  Displays the version of the cord command.	Specifies the output file. If not specified, a.out is used.   Flips  the  first  cachepage
       size  procedures.  When	cord  was  written, the assumption was that procedures would be reordered by procedure density (cycles/byte). This
       option ensures that the densest part of each page following the first cachepage would conflict with  the  least-dense  part  of	the  first
       cachepage.  Specifies the cache size (in bytes) of the machine on which you want to execute. This only affects the -f option. If not speci-
       fied, 65536 is used.  Specifies the maximum number phases allowed. The default is 20.

DESCRIPTION

       The cord command rearranges procedures in an executable object file to maximize efficiency in a machine's cache. By rearranging the  proce-
       dures  properly,  you  can reduce the instruction cache miss rates. The cord command does not attempt to determine the correct ordering; it
       must be given a reorder-file containing the desired procedure order. The reorder file is generated by the ftoc program, which in turn  gen-
       erates a reorder file from a set of profile feedback files (see prof(1)).

       Processed  lines in the reorder file are called procedure lines. Each procedure line must be on a separate source line. Each procedure line
       must contain the source name of the file, followed by a blank, followed by a qualified procedure name. Nested procedures must be  qualified
       x.y, where x is the outer procedure. A newline or blank can follow the procedure name:

       foo.c bar (everything else following is ignored)

       Lines beginning with # are comments, lines beginning with $ are considered cord directive lines. The only directive currently understood is
       $phase. This directive will consider the rest of the file (until the end of file or next $phase) as a new phase of  the	program  and  will
       order  the  procedures  accordingly.   A  procedure  may  appear in more than one phase, resulting in more than one copy of it in the final
       binary. First, cord will try to relocate procedure references to a copy of the procedure belonging to the requesting phase;  otherwise,	it
       will relocate the references to a random copy.

       Use  the  -cord	option	to a compiler driver like cc(1) rather than execute cord directly. The cord options can be specified with -Wc,cor-
       darg0,cordarg1,.... If you have to run cord by hand, you may want to run it once with the driver using the -v option on a  simple  program.
       This will enable you to see the exact passes and the arguments involved in using cord.

									 Warning

       Since cord works from an input list of procedures generated from profile output, the resulting binary is data dependent. In other words, it
       may only perform well on the same input data that generated the profile information, and may perform worse  than  the  original	binary	on
       other data. Furthermore, if the hot areas in the cache do not fit well into one cachepage, performance can degrade.

SEE ALSO

       Commands:  cc(1), ftoc(1), ld(1), prof(1)

       Programmer's Guide

																	   cord(1)