########################################################################
#10/19/2006
#Acer Incorporated.
#SPEC CPU2000 v1.3 Flag Descriptions
#Intel C/C++ Compiler 9.1 for Linux
#Intel Fortran Compiler 9.1 for Linux
########################################################################
========================================================================
General Options (C/C++/FORTRAN)
========================================================================
-fast This option maximizes speed across the entire program.
It sets the following options (IA-32 and EM64T):
-O3 -ipo -no-prec-div -xP -static (Linux)
-O{1|2|3} Optimization-level options:
1: optimize for speed, but disable some optimizations that
increase code size for a small speed benefit. Includes
inline expansion for intrinsic functions, global
optimizations, string pooling optimizations.
2: optimizes for speed (DEFAULT). The -O2 option includes O1
optimizations and in addition enables inlining of
intrinsics and more speed optimizations.
3: builds on -01 and -02 optimizations by enabling high-level
optimization. This level does not guarantee higher performance
unless loop and memory access transformation take place. In
conjunction with -QaxK/-QxK and QaxW/QxW, this switch causes
the compiler to perform more aggressive data dependency
analysis than for -O2. This may result in longer compilation
times.
-Oa[-] Assume [do not assume] no aliasing in program.
-ansi-alias[-] (Linux)
Enable/disable use of ANSI aliasing rules in
optimizations; user asserts that the program adheres to
these rules. The default for C++ is -ansi_alias-
which is that aliasing rules are not assumed. The default for
the Fortran compiler is -Qansi_alias. For C++, the -ansi_alias
flag will enable optimizations that would otherwise be
prevented by potential aliasing.
-ipo (Linux)
Multi-file ip optimizations that includes:
- inline function expansion
- interprocedural constant propogation
- dead code elimination
- propagation of function characteristics
- passing arguments in registers
- loop-invariant code motion
-[no-]prec-div (Linux)
Improves precision of floating point divides.
-prof_gen (Linux)
Instrument program for profiling for the first phase of
two-phase profile guided optimization.
-prof_use (Linux)
Instructs the compiler to produce a profile-optimized
executable and merges available dynamic information (.dyn)
files into a pgopti.dpi file. If you perform multiple
executions of the instrumented program, -Qprof_use merges
the dynamic information files again and overwrites the
previous pgopti.dpi file. Without any other options,
the current directory is searched for .dyn files.
-rcd (Linux)
The Intel compiler uses the -rcd option to improve the
performance of code that requires floating-point-to-integer
conversions.
The system default floating point rounding mode is
round-to-nearest. This means that values are rounded during
floating point calculations. However, the C language requires
floating point values to be truncated when a conversion to an
integer is involved. To do this, the compiler must change the
rounding mode to truncation before each floating
point-to-integer conversion and change it back afterwards.
The -Qrcd option disables the change to truncation of the
rounding mode for all floating point calculations, including
floating point-to-integer conversions. Turning on this option
can improve performance, but floating point conversions to
integer may not conform to C semantics.
-unroll[n] (Linux)
Specifies the maximum number of times to unroll a loop. Omit n
to let the compiler decide whether to perform unrolling or not.
Use n = 0 to disable unroller.
-ax<processor> (Linux)
Directs the compiler to generate processor-specific code if there is a
performance benefit, while also generating generic IA-32 code.
<processor> is the processor for which you want to target your program.
Possible values are:
K: Code is optimized for Intel Pentium III and compatible Intel processors.
W: Code is optimized for Intel Pentium 4 and compatible Intel processors.
N: Code is optimized for Intel Pentium 4 and compatible Intel processors
with Streaming SIMD Extensions 2. The resulting code may contain
unconditional use of features that are not supported on other
processors.
This option also enables new optimizations in addition to Intel
processor-specific optimizations including advanced data layout and
code restructuring optimizations to improve memory accesses for Intel
processors.
B: Code is optimized for Intel Pentium M and compatible Intel processors.
This option also enables new optimizations in addition to Intel
processor-specific optimizations.
P: Code is optimized for Intel?Core?Duo processors, Intel?Core?Solo
processors, Intel?Pentium?4 processors with Streaming SIMD
Extensions 3, and compatible Intel processors with Streaming SIMD
Extensions 3. The resulting code may contain unconditional use of
features that are not supported on other processors.
This option also enables new optimizations in addition to Intel
processor-specific optimizations including advanced data layout and
code restructuring optimizations to improve memory accesses for Intel
processors.
-x<processor> (Linux)
Generate specialized code for processor specified by <codes>
while also generating generic code.
<processor> is the processor for which you want to target your program.
Possible values are:
K: Code is optimized for Intel Pentium III and compatible Intel processors.
W: Code is optimized for Intel Pentium 4 and compatible Intel processors.
N: Code is optimized for Intel Pentium 4 and compatible Intel processors
with Streaming SIMD Extensions 2. The resulting code may contain
unconditional use of features that are not supported on other
processors.
This option also enables new optimizations in addition to Intel
processor-specific optimizations including advanced data layout and
code restructuring optimizations to improve memory accesses for Intel
processors.
B: Code is optimized for Intel Pentium M and compatible Intel processors.
This option also enables new optimizations in addition to Intel
processor-specific optimizations.
P: Code is optimized for Intel?Core?Duo processors, Intel?Core?Solo
processors, Intel?Pentium?4 processors with Streaming SIMD
Extensions 3, and compatible Intel processors with Streaming SIMD
Extensions 3. The resulting code may contain unconditional use of
features that are not supported on other processors.
This option also enables new optimizations in addition to Intel
processor-specific optimizations including advanced data layout and
code restructuring optimizations to improve memory accesses for Intel
processors.
Additional Notes on <codes> N and P:
------------------------------------
The N and P options target your program to run on Intel Pentium 4
and compatible Intel processors. The resulting code might
contain unconditional use of features that are not supported
on other processors. Programs, where the function main() is
compiled with this option, will detect non compatible processors
and generate an error message during execution. These options also
enable new optimizations in addition to Intel processor-specific
optimizations including advanced data layout and code restructuring
optimizations to improve memory accesses for Intel processors.
-Zp{1|2|4|8|16} Specifies the strictest alignment constraint for structure and
union types as one of the following: 1, 2, 4, 8, or 16 (default)
bytes.
-static (Linux)
This option prevents linking with shared libraries. It causes
the executable to link all libraries statically.
-auto-ilp32 (Linux)
This option instructs the compiler to analyze the program to
determine if there are 64-bit pointers which can be safely
shrunk into 32-bit pointers. In order for this option to be
effective the compiler must be able to optimize using the
-ipo/-Qipo option, and must be able to analyze all library/
external calls the program makes. This option imposes the
following restriction on the program:
The program cannot malloc any objects greater than 2**31 bytes
in size.
If the program does not satisfy this restriction, unpredictable
behavior may occur.
=============================================================================
Flags Specific to C/C++
=============================================================================
=================================================================================
Flags Specific to FORTRAN
=================================================================================
-auto (Linux)
Causes all variables to be allocated on the stack, rather than
in local static storage.
-[no-]scalar-rep (Linux)
Enables (DEFAULT) [disables] scalar replacement performed
during loop transformations.
==============================================================================
General Options and Libraries
==============================================================================
The starting tokens "/" and "-" are both equivalent for flags passed to the
compiler. For example, -QxW and /QxW are identical switches.
+FDO PASS1= -Qprof_gen PASS2= -Qprof_use
Using feedback-directed optimization, a profile is generated
on the first pass of compilation and used on the second pass.
shlW32M.lib
MicroQuill SmartHeap Library available from www.microquill.com
===============================================================================
Benchmark-Specific Portability Options
===============================================================================
-DSPEC_CPU2000_LP64
Compile using LP64 programming model.
176.gcc:
-Dalloca=_alloca So as to use the built-in optimized alloca.
/F10000000 176.gcc uses alloca and this option tells the
linker to pre-allocate 10MB of stack. The default
amount of stack allocated is not enough and 176.gcc
crashes with a run-time error
178.galgel:
-FI (Linux)
/FI Fixed-format F90 source code.
/F32000000 Same as with 176.gcc, pre-allocates a 32MB stack
186.crafty:
-DNT_i386 Specifies that it is a Windows NT Intel processor-based
system which makes the compiler use "_int64"
as the 64-bit variable that 186.crafty needs.
253.perlbmk:
-DSPEC_CPU2000_NTOS
This enables the code changes for porting to
Windows get included.
-DPERLDLL On Windows, we need a perl.exe instead of a
perl.exe and perl.dll. This pre-defines ensures
that the changes necessary to get a single, UNIX-style
executible without getting the indirect calls that
can cause a 10% performance degradation. This allows
the Windows-based executible to be as close as possible
to the Unix-based one.
/MT Use the static multi-threaded library else it
will not compile.
254.gap:
-DSYS_HAS_CALLOC_PROTO
-DSYS_HAS_MALLOC_PROTO
These two pre-defines tell of the existence of
malloc and calloc prototypes.
============================================================================================================
BIOS Setting Description
============================================================================================================
1. Hardware Prefetch: Default is enabled.
The NetBurst architecture introduced a hardware prefetch mechanism, which automatically prefetches data into the L2 cache in case of sequential data accesses with constant stride.
2. Adjacent Cache Line Prefetch: Default is enabled.
The adjacent cache line prefetch feature, when enabled, will cause the CPU to fetch 2 adjacent cachelines when updating the cache rather than just a cacheline at a time.