Index for Section 1

Alphabetical listing for C

cord(1)
NAME
  cord - Rearrange procedures in an executable file to facilitate better
  cache mapping

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

OPTIONS
  The cord command accepts these options:

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

  -f  Flip the first cachepage size procedures. The assumption when cord was
      written 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.

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

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

  -p phasemax
      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 procedures
  properly, we end up reducing the instruction cache miss rates.  The cord
  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 ftoc program, which in turn generates 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.  cord options can be specified with
  -Wz,cordarg0,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
  cc(1), ftoc(1), ld(1), prof(1)

  Programmer's Guide