MPI2007 Flag Description
Celestica A2210 ("Serenade") -- Reference Platform

Base Optimization Flags

C benchmarks

• • -O2
  • 
  • COPTIMIZE

  • Specify the basic level of optimization desired.
    The options can be one of the following:

    0    Turn off all optimizations.

    1    Turn on local optimizations that can be done quickly. Do peephole optimizations and instruction scheduling.

    2    Turn on extensive optimization. This is the default.
    The optimizations at this level are generally conservative, in the sense that they are virtually always beneficial and avoid changes which affect such things as floating point accuracy. In addition to the level 1 optimizations, do inner loop unrolling, if-conversion, two passes of instruction scheduling, global register allocation, dead store elimination, instruction scheduling across basic blocks, and partial redundancy elimination.

    3    Turn on aggressive optimization.
    The optimizations at this level are distinguished from -O2 by their aggressiveness, generally seeking highest-quality generated code even if it requires extensive compile time. They may include optimizations that are generally beneficial but may hurt performance.
    This includes but is not limited to turning on the Loop Nest Optimizer, -LNO:opt=1, and setting -OPT:roundoff=1:IEEE_arithmetic=2:Olimit=9000:reorg_common=ON.

    s    Specify that code size is to be given priority in tradeoffs with execution time.

    If no value is specified, 2 is assumed.

• • -LANG:copyinout=OFF
  • 
  • COPTIMIZE

  • -LANG:copyinout : This is a workaround suggested by Qlogic for a severe performance bug in the Pathscale 2.5 Fortran compiler. Several benchmarks (e.g. 121.pop2) take an excessive amount of time to run without specifying this flag.

C++ benchmarks

126.lammps

• • -O2
  • 
  • CXXOPTIMIZE

  • Specify the basic level of optimization desired.
    The options can be one of the following:

    0    Turn off all optimizations.

    1    Turn on local optimizations that can be done quickly. Do peephole optimizations and instruction scheduling.

    2    Turn on extensive optimization. This is the default.
    The optimizations at this level are generally conservative, in the sense that they are virtually always beneficial and avoid changes which affect such things as floating point accuracy. In addition to the level 1 optimizations, do inner loop unrolling, if-conversion, two passes of instruction scheduling, global register allocation, dead store elimination, instruction scheduling across basic blocks, and partial redundancy elimination.

    3    Turn on aggressive optimization.
    The optimizations at this level are distinguished from -O2 by their aggressiveness, generally seeking highest-quality generated code even if it requires extensive compile time. They may include optimizations that are generally beneficial but may hurt performance.
    This includes but is not limited to turning on the Loop Nest Optimizer, -LNO:opt=1, and setting -OPT:roundoff=1:IEEE_arithmetic=2:Olimit=9000:reorg_common=ON.

    s    Specify that code size is to be given priority in tradeoffs with execution time.

    If no value is specified, 2 is assumed.

• • -LANG:copyinout=OFF
  • 
  • CXXOPTIMIZE

  • -LANG:copyinout : This is a workaround suggested by Qlogic for a severe performance bug in the Pathscale 2.5 Fortran compiler. Several benchmarks (e.g. 121.pop2) take an excessive amount of time to run without specifying this flag.

Fortran benchmarks

• • -O2
  • 
  • FOPTIMIZE

  • Specify the basic level of optimization desired.
    The options can be one of the following:

    0    Turn off all optimizations.

    1    Turn on local optimizations that can be done quickly. Do peephole optimizations and instruction scheduling.

    2    Turn on extensive optimization. This is the default.
    The optimizations at this level are generally conservative, in the sense that they are virtually always beneficial and avoid changes which affect such things as floating point accuracy. In addition to the level 1 optimizations, do inner loop unrolling, if-conversion, two passes of instruction scheduling, global register allocation, dead store elimination, instruction scheduling across basic blocks, and partial redundancy elimination.

    3    Turn on aggressive optimization.
    The optimizations at this level are distinguished from -O2 by their aggressiveness, generally seeking highest-quality generated code even if it requires extensive compile time. They may include optimizations that are generally beneficial but may hurt performance.
    This includes but is not limited to turning on the Loop Nest Optimizer, -LNO:opt=1, and setting -OPT:roundoff=1:IEEE_arithmetic=2:Olimit=9000:reorg_common=ON.

    s    Specify that code size is to be given priority in tradeoffs with execution time.

    If no value is specified, 2 is assumed.

• • -LANG:copyinout=OFF
  • 
  • FOPTIMIZE

  • -LANG:copyinout : This is a workaround suggested by Qlogic for a severe performance bug in the Pathscale 2.5 Fortran compiler. Several benchmarks (e.g. 121.pop2) take an excessive amount of time to run without specifying this flag.

Benchmarks using both Fortran and C

• • -O2
  • 
  • COPTIMIZE, FOPTIMIZE

  • Specify the basic level of optimization desired.
    The options can be one of the following:

    0    Turn off all optimizations.

    1    Turn on local optimizations that can be done quickly. Do peephole optimizations and instruction scheduling.

    2    Turn on extensive optimization. This is the default.
    The optimizations at this level are generally conservative, in the sense that they are virtually always beneficial and avoid changes which affect such things as floating point accuracy. In addition to the level 1 optimizations, do inner loop unrolling, if-conversion, two passes of instruction scheduling, global register allocation, dead store elimination, instruction scheduling across basic blocks, and partial redundancy elimination.

    3    Turn on aggressive optimization.
    The optimizations at this level are distinguished from -O2 by their aggressiveness, generally seeking highest-quality generated code even if it requires extensive compile time. They may include optimizations that are generally beneficial but may hurt performance.
    This includes but is not limited to turning on the Loop Nest Optimizer, -LNO:opt=1, and setting -OPT:roundoff=1:IEEE_arithmetic=2:Olimit=9000:reorg_common=ON.

    s    Specify that code size is to be given priority in tradeoffs with execution time.

    If no value is specified, 2 is assumed.

• • -LANG:copyinout=OFF
  • 
  • COPTIMIZE, FOPTIMIZE

  • -LANG:copyinout : This is a workaround suggested by Qlogic for a severe performance bug in the Pathscale 2.5 Fortran compiler. Several benchmarks (e.g. 121.pop2) take an excessive amount of time to run without specifying this flag.

Peak Optimization Flags

C benchmarks

104.milc

• • basepeak = yes

122.tachyon

• • basepeak = yes

C++ benchmarks

126.lammps

• • basepeak = yes

Fortran benchmarks

107.leslie3d

• • basepeak = yes

113.GemsFDTD

• • basepeak = yes

129.tera_tf

• • basepeak = yes

137.lu

• • basepeak = yes

Benchmarks using both Fortran and C

115.fds4

• • basepeak = yes

121.pop2

• • basepeak = yes

127.wrf2

• • basepeak = yes

128.GAPgeofem

• • basepeak = yes

130.socorro

• • basepeak = yes

132.zeusmp2

• • basepeak = yes