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cord(1) [ultrix man page]

cord(1) 						      General Commands Manual							   cord(1)

       cord - rearranges procedures in an executable to facilitate better cache mapping.

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

       The  command rearranges procedures in an executable object to maximize efficiency in a machine's cache. By rearranging the procedures prop-
       erly, the instruction cache miss rate is reduced. The command does not attempt to determine the correct ordering, but is  given	a  reorder
       file containing the desired procedure order. The reorder file is generated by the program which in turn generates a reorder file from a set
       of profile feedback files (see ).

       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 need to be quali-
       fied x.y where x is the outer procedure). A newline or blank can follow the procedure name:
       foo.c bar >>i ignore this stuff<<

       Lines beginning with a pound sign (#) are comments.  Lines beginning with a dollar sign ($) are considered directive lines. The only direc-
       tive  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. Procedures may appear in more than one phase, resulting in  more  than  one
       copy  of  it  in  the final binary.  The command will try to relocate references to a procedure to a copy in the requesting phase's list of
       procedures first and then a random copy if one is not found.

       You should use the -cord option to a compiler driver like rather than execute cord directly. Options to	can  be  specified  with  -Wz,cor-
       darg0,cordarg1,....   If  you have to run manually, you should run it once with the driver using the -v flag on a simple program to see the
       exact passes and their arguments involved in using

       The obj argument is an executable object with its relocation information intact. This can be achieved by passing the -r -z  -d  options	to
       the  linker, The -r linker option maintains relocation information in the object, but will not make it a ZMAGIC file (hence -z) nor will it
       allocate common variables (hence -d) as it would without the option.

       -c cachesize   Specify the cachesize of the machine you want to execute on in bytes. This only affects the  -f  option.	If  not  specified
		      65536 is used.

       -f	      Flip  the  first cachepage size procedures. The assumption when was written was that procedures would be reordered by proce-
		      dure density (cycles/byte). This option ensures that the densest part of each page following the first cachepage would  con-
		      flict with least dense part of the first cachepage.

       -o outputfile  specifies the output file. If not specified, a.out is used.

       -p phasemax    Specifies the maximum number of phases allowed. The default is 20.

       -v	      Prints  verbose  information. This includes listing those procedures considered part of other procedures and cannot be rear-
		      ranged (these are basically assembler procedures that may contain relative branches to other procedures rather than relocat-
		      able ones). The listing also list those procedures in the flipped area (if any) and a mapping of old location to new.

       Since 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 don't fit well into one cachepage, performance can degrade.

See Also
       cc(1), ftoc(1), ld(1), prof(1)

								       RISC								   cord(1)
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