Description of compiler flags for Intel C++ Compiler 8.0 -------------------------------------------------------- Portability flags: -Dalloca=_alloca so as to use the built-in optimized alloc /Fn 176.gcc uses alloca and this options tells the linker to pre-allocate n bytes of stack. The default amount of stack allocated is not enough and 176.gcc crashes with a run-time error -DNT_i386 Specifies that it is a Windows NT Intel processor-based system which makes the compiler use "long long" as the 64-bit variable that 186.crafty needs. -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-define ensures that the changes necessary to get a single, UNIX-style executable without getting the indirect calls that can cause a 10% performance degradation. This allows the Windows-based executable to be as close as possible to the Unix-based one. /MT Use the static multi-threaded library else it will not compile. -DSYS_HAS_CALLOC_PROTO These two pre-defines tell of the existence -DSYS_HAS_MALLOC_PROTO of malloc and calloc prototypes. Optimization Flags: -O2 Optimizes for speed. The -O2 option has the same effect as specifying the following options: -Og, -Oi, -Ot, -Oy, -Ob1, -Gf, -Gs, and -Gy. This options defaults to ON. -O3 Optimizes for speed. Enables high-level optimization. This level does not guarantee higher performance. Using this option may increase the compilation time. Impact on performance is application dependent, some applications may not see a performance improvement. -Oa[-] Assume [not assume] no aliasing -Obn Controls the compiler's inline expansion. The amount of inline expansion performed varies with the value of n as follows: 0: Disables inlining. 1: Enables (default) inlining of functions declared with the __inline keyword. Also enables inlining according to the C++ language. 2: Enables inlining of any function. However, the compiler decides which functions to inline. Enables interprocedural optimizations and has the same effect as -Qip. Default n=1. -Og Enables global optimizations. Default ON. -Ot Enables all speed optimizations. Overrides -Os -Oi[-] Enables/disables inline expansion of intrinsic functions. Default Enabled. -Ow[-] Assume[not assume] no aliasing within functions, but assume aliasing across calls. -Oy[-] Enables [disables] the use of the EBP register in optimizations. When you disable with -Oy-, the EBP register is used as frame pointer. Default Enabled. -Gf Enables string-pooling optimization. Default ON. -Gs[n] Disables stack-checking for routines with n or more bytes of local variables and compiler temporaries. Default: n=4096 -Gy Packages functions to enable linker optimization. Default ON. -Qax{K|W|N} Generates specialized code for processor specific codes K, W, N while also generating generic IA-32 code. K = Intel Pentium III and compatible Intel processors W = Intel Pentium 4 and compatible Intel processors N = Intel Pentium 4 and compatible Intel processors. These options also enable advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors. -Qx{K|W|N} Generate specialized code to run exclusively on processors supporting the extensions indicated by as described above. -Qip Enables single-file interprocedural optimizations within a file. Same as -Ob2. -Qipo multi-file ip optimizations that includes: - inline function expansion - interprocedural constant propagation - monitoring module-level static variables - dead code elimination - propagation of function characteristics - passing arguments in registers - loop-invariant code motion -Qprof_gen Instruments the program for profiling: to get the execution count of each basic block. -Qprof_use Enables the use of profiling dynamic feedback information during optimization. Turns on -Qfnsplit. -Qrcd Enables[disables] fast conversions of floating-point to integer conversions. This option does not guarantee that any particular rounding mode will be used. -Qansi_alias[-] -Qansi_alias directs the compiler to assume[not assume] the following: - Arrays are not accessed out of bounds. - Pointers are not cast to non-pointer types, and vice-versa. - References to objects of two different scalar types cannot alias. For example, an object of type int cannot alias with an object of type float, or an object of type float cannot alias with an object of type double. If your program satisfies the above conditions, setting the -Qansi_alias flag will help the compiler better optimize the program. However, if your program does not satisfy one of the above conditions, the -Qansi_alias flag may lead the compiler to generate incorrect code. -GR[-] Enables[disables] C++ Run Time Type Information (RTTI). -GX[-] Enables[disables] C++ Exception Handling. -fast Maximize speed across the entire program. Turns on -O3 and -Qipo. -Qfp_port round fp results at assignments & casts (some speed impact) -Qprefetch Enable prefetch insertion. Default ON. -Qunroll[n] Specifies the maximum number of times to unroll a loop. n=0 disables loop unrolling. -Qoption,tool,optlist -Qoption passes an option specified by optlist to a tool, where optlist is a comma-separated list of options. tool Description ------------------------------------ cpp Specifies the compiler front-end preprocessor c Specifies the C++ compiler asm Specifies the assembler link Specifies the linker oplist Indicates one or more valid argument strings for the designated program. If the argument is a command-line option, you must include the hyphen. If the argument contains a space or tab character, you must enclose the entire argument in quotation characters (""). You must separate multiple arguments with commas -Qoption can be used with the -Qipo flag to refine IPO. The valid options that can be used for this purpose are: -ip_args_in_regs=0 Disables the passing of arguments in registers. -ip_ninl_max_stats=n Sets the valid max number of intermediate language statements for a function that is expanded in line. The number n is a positive integer. The number of intermediate language statements usually exceeds the actual number of source language statements. The default value for n is 230. The compiler uses a larger limit for user inline functions. -ip_ninl_min_stats=n Sets the valid min number of intermediate language statements for a function that is expanded in line. The number n is a positive integer. The default values for ip_ninl_min_stats are: IA-32 compiler: ip_ninl_min_stats = 7 -ip_ninl_max_total_stats=n Sets the maximum increase in size of a function, measured in intermediate language statements, due to inlining. n is a positive integer whose default value is 2000. shlW32M.lib: MicroQuill SmartHeap Library available from http://www.microquill.com/ -Zp{1|2|4|8|16} Specifies the strictest alignment constraint for structure and union types as 1, 2. 4. 8 or 16 bytes. Default is 16. -arch:SSE Enables the compiler to use SSE instructions. -arch:SSE2 Enables the compiler to use SSE2 instructions. -EHc Specifies that C functions do not throw exceptions. Default ON. -G7 Target optimization to Intel Pentium 4 processors. Default ON. -ML Compiles and links with the static, single-thread C run time library. Default ON. -QA Enables all predefined macros and all assertions. Default ON. -Qfnsplit Enables function splitting. Default ON. -Qms1 Instructs the compiler to enable most Microsoft compatability bugs. Default ON. -Qmspp Enables Microsoft C++ 6.0 Processor Pack binary compatability. Default ON. -Qpc64 Enables floating-point significand precision control. The value is used to round the significand to the correct number of bits. The value must be either 32, 64, or 80. Default ON. -Qpchi Enables precompiled header files coexistence to reduce build time. Default ON. -Qsfalign8 May align stack for functions with 8 or 16 byte vars. Default ON. -Qvc7 Enables compatability with Visual C++ .NET. Default ON. -Qvec_report1 Indicate vectorized loops in diagnostic information. Default ON. -vmb Selects the smallest representation for pointers to members. Use this option if you define each class before you declare a pointer to a member of the class. Default ON. Description of compiler flags for Intel C++ Compiler 9.0 -------------------------------------------------------- Portability flags: -Dalloca=_alloca so as to use the built-in optimized alloc /Fn 176.gcc uses alloca and this options tells the linker to pre-allocate n bytes of stack. The default amount of stack allocated is not enough and 176.gcc crashes with a run-time error -DNT_i386 Specifies that it is a Windows NT Intel processor-based system which makes the compiler use "long long" as the 64-bit variable that 186.crafty needs. -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-define ensures that the changes necessary to get a single, UNIX-style executable without getting the indirect calls that can cause a 10% performance degradation. This allows the Windows-based executable to be as close as possible to the Unix-based one. /MT Use the static multi-threaded library else it will not compile. -DSYS_HAS_CALLOC_PROTO These two pre-defines tell of the existence -DSYS_HAS_MALLOC_PROTO of malloc and calloc prototypes. Optimization Flags: -O2 Optimizes for speed. The -O2 option includes the following options: -Og, -Oi-, -Os, -Oy, -Ob1, and -Gs This options defaults to ON. This option also enables. * inlining of intrinsics * Intra-file interprocedural optimizations including: * inlining * constant propagation * forward substitution * routine attribute propagation * variable address-taken analysis * dead static function elimination * removal of unreferenced variables. * The following performance optimizations: * copy propogation. * dead-code elimination * global register allocation * global instruction scheduling and control speculation * loop unrolliing * optimized code selection * partial redundancy elimination * strength reduction/induction variable simplification * variable renaming * exception handling optimizations * tail recursions * peephole optimizations * structure assignment lowering and optimizations * dead store elimination -O3 Optimizes for speed. Enables high-level optimization. This level does not guarantee higher performance. Using this option may increase the compilation time. Impact on performance is application dependent, some applications may not see a performance improvement. The optimizations include: * All optimizations done with -O2 * loop unrolling, including instruction scheduling * code replication to eliminate branches * padding the size of certain power-of-two arrays to allow more efficient cache use. * When used with -Qax or -Qx, it causes the compiler to perform more aggressive data dependency analysis than for -O2. -Oa[-] Assume [not assume] no aliasing. Default Disabled. -Obn Controls the compiler's inline expansion. The amount of inline expansion performed varies with the value of n as follows: 0: Disables inlining. Statement functions are always inlined. 1: Enables (default) inlining of functions declared with the __inline keyword. Also enables inlining according to the C++ language. 2: Enables inlining of any function. However, the compiler decides which functions to inline. Enables interprocedural optimizations and has the same effect as -Qip. Default n=2. -Og Enables global optimizations. Default ON. -Ot Enables all speed optimizations. Overrides -Os -Oi[-] Enables/disables inline expansion of intrinsic functions. Default Enabled. -Ow[-] Assume[not assume] no cross function aliasing. -Oy[-] Enables [disables] the use of the EBP register in optimizations. When you disable with -Oy-, the EBP register is used as frame pointer. -Oy has the effect of reducing the number of general-purpose registers by 1, and can produce slightly less efficient code. Default Enabled. -Gf Enables string-pooling optimization. -Gs[n] Disables stack-checking for routines with n or more bytes of local variables and compiler temporaries. Default: n=4096 -Gy Packages functions to enable linker optimization. Default ON. -Qax{K|W|N} Generates specialized code for processor specific codes K, W, N while also generating generic IA-32 code. K = Intel Pentium III and compatible Intel processors W = Intel Pentium 4 and compatible Intel processors N = Intel Pentium 4 and compatible Intel processors. These options also enable advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors. -Qx{K|W|N} Generate specialized code to run exclusively on processors supporting the extensions indicated by as described above. -Qip Enables single-file interprocedural optimizations within a file. -Qipo Enables multi-file ip optimizations which allows inline function expansion for calls to functions defined in separate files. The compiler decides whether to create one or more object files based on an estimate of the size of the application. It generates one object file for small applications and two for large ones. -Qprof_gen Instruments the program for profiling: to get the execution count of each basic block. -Qprof_use Enables the use of profiling dynamic feedback information during optimization. Turns on -Qfnsplit. Forces function grouping. -Qrcd Enables[disables] fast conversions of floating-point to integer conversions. This option does not guarantee that any particular rounding mode will be used. -Qansi_alias[-] -Qansi_alias directs the compiler to assume the following: - Arrays are not accessed out of bounds. - Pointers are not cast to non-pointer types, and vice-versa. - References to objects of two different scalar types cannot alias. For example, an object of type int cannot alias with an object of type float, or an object of type float cannot alias with an object of type double. If your program satisfies the above conditions, setting the -Qansi_alias flag will help the compiler better optimize the program. However, if your program does not satisfy one of the above conditions, the -Qansi_alias flag may lead the compiler to generate incorrect code. -GR[-] Enables[disables] C++ Run Time Type Information (RTTI). -GX[-] Enables[disables] C++ Exception Handling. Default Disabled. -fast Maximize speed across the entire program. Turns on -O3, -Qipo, -Qprec-div-, and -QxP. -Qfp_port round fp results at assignments & casts (some speed impact) -Qprefetch Enable prefetch insertion. Default ON. -Qunroll[n] Specifies the maximum number of times to unroll a loop. n=0 disables loop unrolling. Default: the compiler uses default heuristics when unrolling loops. -Qoption,tool,optlist -Qoption passes an option specified by optlist to a tool, where optlist is a comma-separated list of options. tool Description ------------------------------------ cpp Specifies the compiler front-end preprocessor c Specifies the C++ compiler asm Specifies the assembler link Specifies the linker oplist Indicates one or more valid argument strings for the designated program. If the argument is a command-line option, you must include the hyphen. If the argument contains a space or tab character, you must enclose the entire argument in quotation characters (""). You must separate multiple arguments with commas NOTE: If 'tool' is incorrectly specified, the compiler gives an warning and the option is ignored. For example, if -Qoption,f,... is used with the Intel C++ compiler, the option is ignored with an warning. -Qoption can be used with the -Qipo flag to refine IPO. The valid options that can be used for this purpose are: -ip_args_in_regs=0 Disables the passing of arguments in registers. -ip_ninl_max_stats=n Sets the valid max number of intermediate language statements for a function that is expanded in line. The number n is a positive integer. The number of intermediate language statements usually exceeds the actual number of source language statements. The default value for n is 230. The compiler uses a larger limit for user inline functions. -ip_ninl_min_stats=n Sets the valid min number of intermediate language statements for a function that is expanded in line. The number n is a positive integer. The default values for ip_ninl_min_stats are: IA-32 compiler: ip_ninl_min_stats = 7 -ip_ninl_max_total_stats=n Sets the maximum increase in size of a function, measured in intermediate language statements, due to inlining. n is a positive integer whose default value is 2000. shlW32M.lib: MicroQuill SmartHeap Library available from http://www.microquill.com/ -Zp{1|2|4|8|16} Specifies the strictest alignment constraint for structure and union types as 1, 2. 4. 8 or 16 bytes. Default is 16. -arch:SSE Enables the compiler to use SSE instructions. -arch:SSE2 Enables the compiler to use SSE2 instructions. -Qprec-div[-] Enables[disables] improved precision of floating-point divides. Disabling may slightly improve speed. Default Enabled. -Qpc64 Enables floating-point significand precision control. The value is used to round the significand to the correct number of bits. The value must be either 32, 64, or 80. Default ON. Description of compiler flags for Intel Fortran Compiler 9.0 ------------------------------------------------------------ Portability flags: -FI Fixed-format F90 source code. -F32000000 Same as with 176.gcc, pre-allocates a 32MB stack Optimization Flags: -O2 Optimizes for speed. The -O2 option includes the following options: -Og, Ot, -Oy, -Ob1, and -Gs This options defaults to ON. This option also enables. * inlining of intrinsics * Intra-file interprocedural optimizations including: * inlining * constant propagation * forward substitution * routine attribute propagation * variable address-taken analysis * dead static function elimination * removal of unreferenced variables. * The following performance optimizations: * copy propogation. * dead-code elimination * global register allocation * global instruction scheduling and control speculation * loop unrolliing * optimized code selection * partial redundancy elimination * strength reduction/induction variable simplification * variable renaming * exception handling optimizations * tail recursions * peephole optimizations * structure assignment lowering and optimizations * dead store elimination -O3 Optimizes for speed. Enables high-level optimization. This level does not guarantee higher performance. Using this option may increase the compilation time. Impact on performance is application dependent, some applications may not see a performance improvement. The optimizations include: * All optimizations done with -O2 * loop unrolling, including instruction scheduling * code replication to eliminate branches * padding the size of certain power-of-two arrays to allow more efficient cache use. * When used with -Qax or -Qx, it causes the compiler to perform more aggressive data dependency analysis than for -O2. -Oa[-] Assume [not assume] no aliasing -Ob{0|1|2} Controls the compiler's inline expansion. The amount of inline expansion performed varies as follows: -Ob0: Disable inlining. -Ob1: Disables (default) inlining unless -Qip or -Ob2 is specified. Enables inlining of functions. -Ob2: Enables inlining of any function. However, the compiler decides which functions to inline. Enables interprocedural optimizations and has the same effect as -Qip. -Og Enables global optimizations. -Ot Enables all speed optimizations. -Oi[-] Enables/disables inline expansion of intrinsic functions -Ow[-] Assume[not assume] no cross-function aliasing. -Ox Same as the -O2 option: enables -Gs, and -Ob1, -Og, -Oy, and -Ot. -Oy[-] Enables [disables] the use of the EBP register in optimizations. When you disable with -Oy-, the EBP register is used as frame pointer. -auto Determines whether local variables are put on the run-time stack. -Gf Enables string-pooling optimization. -Gs[n] Disables stack-checking for routines with n or more bytes of local variables and compiler temporaries. Default: n=4096 -Gy Packages functions to enable linker optimization. -fast Maximize speed across the entire program. Turns on -O3, -Qprec-div-, -QxP, and -Qipo. -Qax{K|W|N|P} Generates specialized code for processor specific codes K, W, N, P while also generating generic IA-32 code. K = Intel Pentium III and compatible Intel processors W = Intel Pentium 4 and compatible Intel processors N = Intel Pentium 4 and compatible Intel processors. These option also enable advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors. P = Intel Pentium 4 processor with Streaming SIMD 3 (SSE3) support. These option also enable advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors. -Qx{K|W|N|P} Generate specialized code to run exclusively on processors supporting the extensions indicated by as described above. -Qip Enables single-file interprocedural optimizations within a file. -Qipo multi-file ip optimizations that includes: - inline function expansion - interprocedural constant propagation - monitoring module-level static variables - dead code elimination - propagation of function characteristics - passing arguments in registers - loop-invariant code motion -Qprof_gen Instruments the program for profiling: to get the execution count of each basic block. -Qprof_use Enables the use of profiling dynamic feedback information during optimization. -Qrcd Enables[disables] fast conversions of floating-point to integer conversions. This option does not guarantee that any particular rounding mode will be used. -Qansi_alias Enables (default) or disables the compiler to assume that the program adheres to the ANSI Fortran type aliasablility rules. For example, an object of type real cannot be accessed as an integer. You should see the ANSI Standard for the complete set of rules. -Qscalar_rep[-] Enables[disables] scalar replacement performed during loop transformations. (requires /O3). -Qunroll[n] Specifies the maximum number of times to unroll a loop. n=0 disables loop unrolling. -Qprefetch[-] Enables[disables] prefetch insertion (requires -O3). -Qoption,tool,optlist -Qoption passes an option specified by optlist to a tool, where optlist is a comma-separated list of options. tool Description ------------------------------------ fpp Specifies the Fortran preprocessor f Specifies the Fortran compiler asm Specifies the assembler link Specifies the linker oplist Indicates one or more valid argument strings for the designated tool. You must separate multiple arguments with commas. -Qoption can be used with the -Qipo flag to refine IPO. The valid option list that can be used for this purpose are -ip_args_in_regs=0 Disables the passing of arguments in registers. -ip_ninl_max_stats=n Sets the valid max number of intermediate language statements for a function that is expanded in line. The number n is a positive integer. The number of intermediate language statements usually exceeds the actual number of source language statements. The default value for n is 230. The compiler uses a larger limit for user inline functions. -ip_ninl_min_stats=n Sets the valid min number of intermediate language statements for a function that is expanded in line. The number n is a positive integer. The default values for ip_ninl_min_stats are: IA-32 compiler: ip_ninl_min_stats = 7 -ip_ninl_max_total_stats=n Sets the maximum increase in size of a function, measured in intermediate language statements, due to inlining. n is a positive integer whose default value is 2000. shlW32M.lib: MicroQuill SmartHeap Library available from http://www.microquill.com/ -Zp{1|2|4|8|16} Specifies the strictest alignment constraint for structure and union types as 1, 2. 4. 8 or 16 bytes. Default is 16. -Qprec-div[-] Enables[disables] improved precision of floating-point divides. Disabling may slightly improve speed. Default Enabled. Other Notes: ------------ "/" and "-" are both allowable starting tokens for flags passed to the compiler i.e. -QxK and /QxK are identical switches. Compiler options for PGI Fortran compiler 6.0 for Windows XP IA32 ----------------------------------------------------------------- The optimization levels and their meanings are as follows: -lacml Link with the AMD Core Math Library 2.5.3, packaged with the compiler. Also available at www.amd.com -O0 A basic block is generated for each Fortran statement. No scheduling is done between statements. No global optimizations are performed. -O1 Scheduling within extended basic blocks is performed. Some register allocation is performed. No global optimizations are performed. -O2 All level 1 optimizations are performed. In addition, scalar optimizations such as induction recognition and loop invariant motion are performed by the global optimizer. -O3 This level performs all level-one and level-two optimizations and enables more aggressive hoisting and scalar replacement optimizations. -fast Equivalent to "-O2 -Munroll=c:1 -Mnoframe -Mlre" -fastsse Equivalent to "-fast -Mscalarsse -Mvect=sse -Mcache_align -Mflushz" -Mpfi Generate profile feedback instrumentation; this includes extra code to collect run-time statistics to be used in a subsequent compile; -Mpfi must also appear when the program is linked. When the program is run, a profile feedback file pgfi.out will be generated; see -Mpfo. -Mpfo Enable profile feedback optimizations; there must be a profile feedback file pgfi.out in the current directory, which contains the result of an execution of the program compiled with -Mpfi. -Mcache_align Align unconstrained objects of length greater than or equal to 16 bytes on cache-line boundaries. An unconstrained object is a data object that is not a member of an aggregate structure or common block. This option does not affect the alignment of allocatable or automatic arrays. Note: To effect cache-line alignment of stack-based local variables, the main program or function must be compiled with -Mcache_align. -Mfixed Process source using Fortran90 freeform specifications. -Mflushz Set SSE MXCSR register to flush-to-zero mode. -Mipa=[option] Enables interprocedural analysis with the specified option. The valid options are: -Mipa=align Instructs the IPA to recognize when pointer targets are all cache-line aligned, allowing better SSE code generation. -Mipa=arg Instructs the IPA to remove arguments replaced by -Mipa=ptr,const -Mipa=const Enable propagation of constants across procedure calls. -Mipa=fast Equivalent to: -Mipa=align,arg,const,globals,f90ptr,shape,localarg,ptr,vestigial -Mipa=f90ptr Enable Fortran 90 pointer disambiguation across procdure calls. -Mipa=globals Instructs the IPA to optimize references to globals when not used in procedure calls. -Mipa=inline Automatically determine which functions to inline -Mipa=safe Assume unknown function references are safe -Mipa=localarg Externalizes local variables for use with -Mipa=arg -Mipa=ptr Instructs the IPA to perform pointer disambiguation across procedure calls. -Mipa=vestigial Instructs the IPA to eliminate functions that are not called. -Mlre Enables loop-carried redundancy elimination. -Mnoframe Eliminate operations that set up a true stack frame pointer for functions. -Mnovect Disables the vectorizer. -Mscalarsse Utilize the SSE (Streaming SIMD(Single Instruction Multiple Data) Extensions) and SSE2 instructions to perform the operations coded. This implies -Mflushz. -Munix Use UNIX calling conventions, no trailing underscores. -Munroll Invokes the loop unroller. This also sets the optimization level to 2 if the level is set to less than 2. :m Instructs the compiler to completely unroll loops with a constant loop count less than or equal to m, a supplied constant. If this value is not supplied, the m count is set to 4. n:u Instructs the compiler to unroll u times, a loop which is not completely unrolled, or has a non-constant loop count. If u is not supplied, the unroller computes the number of times a candidate loop is unrolled. -Mvect=sse Instructs the vectorizer to search for loops, and where possible, use the SSE or SSE2 and prefetch instructions (depending on which processor is targeted). Compiler options for PGI C compiler 6.0 for Windows XP ------------------------------------------------------ The optimization levels and their meanings are as follows: -lacml Link with the AMD Core Math Library 2.5.3. Available from www.amd.com -O0 A basic block is generated for each C statement. No scheduling is done between statements. No global optimizations are performed. -O1 Scheduling within extended basic blocks is performed. Some register allocation is performed. No global optimizations are performed. -O2 All level 1 optimizations are performed. In addition, scalar optimizations such as induction recognition and loop invariant motion are performed by the global optimizer. -O3 This level performs all level-one and level-two optimizations and enables more aggressive hoisting and scalar replacement optimizations. -fast Equivalent to "-O2 -Munroll=c:1 -Mnoframe -Mlre" -fastsse Equivalent to "-fast -Mscalarsse -Mvect=sse -Mcache_align -Mflushz" -Mpfi Generate profile feedback instrumentation; this includes extra code to collect run-time statistics to be used in a subsequent compile; -Mpfi must also appear when the program is linked. When the program is run, a profile feedback file pgfi.out will be generated; see -Mpfo. -Mpfo Enable profile feedback optimizations; there must be a profile feedback file pgfi.out in the current directory, which contains the result of an execution of the program compiled with -Mpfi. -Mcache_align Align unconstrained objects of length greater than or equal to 16 bytes on cache-line boundaries. An unconstrained object is a data object that is not a member of an aggregate structure or common block. This option does not affect the alignment of allocatable or automatic arrays. Note: To effect cache-line alignment of stack-based local variables, the main program or function must be compiled with -Mcache_align. -Mflushz Set SSE MXCSR register to flush-to-zero mode. -Mipa=[option] Enables interprocedural analysis with the specified option. The valid options are: -Mipa=align Instructs the IPA to recognize when pointer targets are all cache-line aligned, allowing better SSE code generation. -Mipa=arg Instructs the IPA to remove arguments replaced by -Mipa=ptr,const -Mipa=const Enable propagation of constants across procedure calls. -Mipa=fast Equivalent to: -Mipa=align,arg,const,globals,f90ptr,shape,localarg,ptr,vestigial -Mipa=f90ptr Enable Fortran 90 pointer disambiguation across procdure calls. -Mipa=globals Instructs the IPA to optimize references to globals when not used in procedure calls. -Mipa=inline Automatically determine which functions to inline -Mipa=safe Assume unknown function references are safe -Mipa=localarg Externalizes local variables for use with -Mipa=arg -Mipa=ptr Instructs the IPA to perform pointer disambiguation across procedure calls. -Mipa=vestigial Instructs the IPA to eliminate functions that are not called. -Mlre Enables loop-carried redundancy elimination. -Mnoframe Eliminate operations that set up a true stack frame pointer for functions. -Mnovect Disables the vectorizer. -Mscalarsse Utilize the SSE (Streaming SIMD(Single Instruction Multiple Data) Extensions) and SSE2 instructions to perform the operations coded. This implies -Mflushz. -Munix Use UNIX calling conventions, no trailing underscores. -Munroll Invokes the loop unroller. This also sets the optimization level to 2 if the level is set to less than 2. c:m Instructs the compiler to completely unroll loops with a constant loop count less than or equal to m, a supplied constant. If this value is not supplied, the m count is set to 4. n:u Instructs the compiler to unroll u times, a loop which is not completely unrolled, or has a non-constant loop count. If u is not supplied, the unroller computes the number of times a candidate loop is unrolled. -Mvect=sse Instructs the vectorizer to search for loops, and where possible, use the SSE or SSE2 and prefetch instructions (depending on which processor is targeted). Description of compiler flags for PathScale EKOPath(TM) Compiler Suite (Fortran, C and C++ compilers) ----------------------------------------------------------------------------------------------------- Portability Flags: -DSPEC_CPU2000_LP64 Compile using LP64 programming model. -DLINUX_i386 Linux Intel system, use "long long" as 64bit variable. -DHAS_ERRLIST Prog env provides specification for "sys_errlist[]". -DNDEBUG Defining this disables any assert macros used for debugging. -DSPEC_CPU2000_NEED_BOOL Use SPEC provided definition of the boolean type. -DSPEC_CPU2000_LINUX_I386 Compile for an I386 system running Linux. -DPSEC_CPU2000_GLIBC22 Compatibility with 2.2 & later versions of glibc -DSYS_IS_USG Specifies that the operating system is USG compliant. -DSYS_HAS_TIME_PROTO Do not explicitly declare time(). -DSYS_HAS_IOCTL_PROTO Do not explicitly declare ioctl(). -DSYS_HAS_ANSI System is ANSI compliant. -DSYS_HAS_CALLOC_PROTO Do not explicitly declare calloc(). -fixedform tells f90 compiler to use fixed format (F77 72 column format), instead of F90 free format. Optimization Flags: Some suboptions either enable or disable the feature. To enable a feature, either specify only the suboption name or specify =1, =ON, or =TRUE. Disabling a feature, is accomplished by adding =0, =OFF, or =FALSE. These values are insensitive to case: 'on' & 'ON' mean the same thing. Below, ON & OFF indicate the enabling or disabling of a feature. -CG[:...] Code Generation option group: control the optimizations and transformations of the instruction-level code generator. -CG:cflow=(ON|OFF) A value of OFF disables control flow optimization in the code generation. Default is ON. -CG:gcm=(ON|OFF) Specifying OFF disables the instruction-level global code motion optimization phase. The default is ON. -CG:load_exe=n Specifies the threshold for subsuming a memory load operation into the operand of an arithmetic instruction. The value of 0 turns off this subsumption optimization. The default is 1, when this subsumption is performed only when the result of the load has only one use. This subsumption is not performed if the number of times the result of the load is used exceeds the value n, a non-negative integer. -CG:local_fwd_sched=(ON|OFF) Changes the instruction scheduling algorithm to work forward instead of backward for the instructions in each basic block. The default is OFF. -CG:movnti=N Convert ordinary stores to non-temporal stores when writing memory blocks of size larger than N KB. When N is set to 0, this transformation is avoided. The default value is 120 (KB). -CG:p2align=(ON|OFF) Align loop heads to 64-byte boundaries. The default is OFF. -CG:p2align_freq=n Aligns branch targets based on execution frequency. This option is meaningful only under feedback-directed compilation. The default value n=0 turns off the alignment optimization. Any other value specifies the frequency threshold at or above which this alignment will be performed by the compiler. -CG:prefetch=(ON|OFF) Turning this OFF suppresses any generation of prefetch instructions in the code generator. This has the same effect as -LNO:prefetch=0. The default is ON which implies using default prefetch algorithms. -CG:prefetchnta=(ON|OFF) Prefetch when data is non-temporal at all levels of the cache hierarchy. This is for data streaming situations in which the data will not need to be re-used soon. The default is OFF. -fb_create Used to specify that an instrumented executable program is to be generated. Such an executable is suitable for producing feedback data files with the specified prefix for use in feedback-directed compilation (FDO). The commonly used prefix is "fbdata". This is OFF by default. -fb_opt Used to specify feedback-directed compilation (FDO) by extracting feedback data from files with the specified prefix, which were previously generated using -fb_create. The commonly used prefix is "fbdata". This optimization is off by default. -fno-exceptions Tells the compiler that the program does not use exception handling, so it can perform more aggressive optimization in the code. The generation of exception handling constructs is also suppressed. Under this flag, code that uses exception handling cannot be guaranteed to work correctly. Note that the absence of exception handling construct does not mean that the function can be compiled with this flag. For exception handling to work preperly, the scopes crossed between throwing and catching an exception must all have been compiled with exceptions on. -fno-math-errno Do not set ERRNO after calling math functions that are executed with a single instruction, e.g., sqrt. A program that relies on IEEE exceptions for math error handling may want to use this flag for speed while maintaining IEEE arithmetic compatibility. This is implied by -Ofast. The default is -fmath-errno. -GRA:optimize_boundary=(ON|OFF) Allow the Global Register Allocator to allocate the same register to different variables in the same basic-block. Default is OFF. -INLINE:aggressive=(ON|OFF) Tells the compiler to be more aggressive about inlining. The default is -INLINE:aggressive=OFF. -IPA[:...] IPA option group: control the inter-procedural analyses and transformations performed. Note that giving just the group name without any options, i.e., -IPA, will invoke the interprocedural analyzer. -IPA is off by default unless -Ofast is specified. -ipa Same as -IPA alone. -IPA:callee_limit=(n) Functions whose size exceeds this limit will never be automatically inlined by the compiler. The default is n=2000. -IPA:min_hotness=N Is applicable only under feedback compilation. A call site's invocation count must be at least N befre it can be inlined by IPA. The default is 10. -IPA:ctype=(ON|OFF) Turns on optimizations that speed up interfaces to the constructs defined in ctype.h by assuming that the program will not be run in a multi-threaded environment. The default is OFF. -IPA:field_reorder=(ON|OFF) Enables the re-ordering of fields in large structs based on their reference patterns in feedback compilation to minimize data cache misses. The default is OFF. -IPA:linear=(ON|OFF) Controls conversion of a multi-dimensional array to a single dimensional (linear) array that covers the same block of memory. When inlining Fortran subroutines, IPA tries to map formal array parameters to the shape of the actual parameter. In the case that it cannot map the parameter, it linearizes the array reference. By default, IPA will not inline such callsites because they may cause performance problems. The default is OFF. -IPA:plimit=(n) Inline calls to a procedure until the procedure has grown to size of n. The default is 2500. -IPA:pu_reorder=(0|1|2) Controls the phase that optimizes the layout of the program units (functions) in the program. 0 = Disables procedure reordering (default) 1 = Reorder based on the frequency in which different procedures are invoked. 2 = Reorder based on caller-callee relationship. -IPA:small_pu=(n) A procedure with size smaller than n is not subjected to the plimit restriction.The default is n=30 -IPA:space=N Inline until a program expansion of N% is reached. For example, -IPA:space=20 limits code expansion due to inlining to approx- imately 20%. Default is no limit. -IPA:use_intrinsic[=(ON|OFF)] Enable/disable loading the intrinsic version of standard library functions. The default is OFF. -L -lacml The flags above are needed to use the PathScale compiler to link with the ACML (AMD Core Math Library) library. ACML is available as a free download from http://www.developwithamd.com/acml. -LANG:short_circuit_conditionals=(ON|OFF) Handles .AND. and .OR. via short-circuiting, in which the second operand is not evaluated if unnecessary, even if it contains side effects. Applies only to Fortran. Default is ON. -LNO: option group specifies options and transformations performed on loop nests. The -LNO: option group is enabled only if the -O3 option is also specified on the compiler command line. -LNO:blocking[=(ON|OFF)] Enable/disable the cache blocking transformation. The default is on at -O3 or higher. -LNO:fission=(0|1|2) This option controls loop fission. The options can be one of the following: 0 = Disables loop fission (default) 1 = Performs normal fission as necessary 2 = Specifies that fission be tried before fusion If -LNO:fission=1:fusion=1 or -LNO:fission=2:fusion=2 are spec- ified, then fusion is performed. -LNO:full_unroll,fu=N Fully unroll innermost loops with trip_count <= N inside LNO. N can be any integer between 0 and 100. The default value for N is 5. Setting this flag to 0 disables full unrolling of small trip count loops inside LNO. -LNO:full_unroll_size=N Fully unroll innermost loops with unrolled loop size <= N inside LNO. N can be any integer between 0 and 10000. The conditions implied by the full_unroll option must also be satisfied for the loop to be fully unrolled. The default value for N is 1600. -LNO:full_unroll_outer=(ON|OFF) Control the full unrolling of loops with known trip count that do not contain a loop and are not contained in a loop. The conditions implied by both the full_unroll and the full_unroll_size options must be satisfied for the loop to be fully unrolled. The default is OFF. -LNO:fusion=n Perform loop fusion, n: 0 - off, 1 - conservative, 2 - aggressive. The default is 1. -LNO:opt=(0|1) This option controls the LNO optimization level. The options can be one of the following: 0 = Disable nearly all loop nest optimizations. 1 = Perform full loop nest transformations. This is the default. -LNO:prefetch[=(0|1|2|3)] Specify level of prefetching. 0 = Prefetch disabled. 1 = Prefetch is done only for arrays that are always referenced in each iteration of a loop, the default. 2 = Prefetch is done without the above restrictions. 3 = Most aggressive. -LNO:prefetch_ahead=n Prefetch n cache line(s) ahead. The default is 2. -LNO:sclrze=(ON|OFF) Turns on/off the optimization that replaces an array by a scalar variable. The default is ON. -LNO:simd=(0|1|2) This option enables or disables inner loop vectorization. 0 = Turn off the vectorizer. 1 = (Default) Vectorize only if the compiler can determine that there is no undesirable performance impact due to sub-optimal alignment. Vectorize only if vectorization does not introduce accuracy problems with floating-point operations. 2 = Vectorize without any constraints (most aggressive). -LNO:simd_reduction=(ON|OFF) This controls whether reduction loops will be vectorized. Default is ON. -m32 Generates code according to the 32-bit ABI, also known as x86 or IA32. -m64 Compile for 64-bit ABI, also known as AMD64, x86_64, or IA32e. This is the default. -m3dnow Enable use of 3DNow instructions. The default is OFF. -mcpu=(opteron|athlon64|athlon64fx|em64t|pentium4|xeon|anyx86|auto) Compiler will optimize code for selected platform. auto means to optimize for the platform that the compiler is running on, which the compiler determines by reading /proc/cpuinfo. anyx86 means a generic 32-bit x86 processor without SSE2 support. The default is opteron. -msse2 Enable use of SSE2 instructions. This is the default under both -m64 and -m32. -mno-sse2 This flag is only applicable to -m32. -mno-sse2 is ignored under -m64 with a warning. -O or -O2 Turn on extensive optimization. The optimizations at this level are generally conservative, in the sense that they (1) are virtually always beneficial, (2) provide improvements commensurate to the compile time spent to achieve them, and (3) avoid changes which affect such things as floating point accuracy. -O3 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 which are generally beneficial but occasionally hurt performance. This includes but is not limited to turning on the Loop Nest Optimizer, -LNO:opt=1, and setting -OPT:ro=1:IEEE_arith=2:Olimit=9000. -Ofast Equivalent to "-O3 -ipa -OPT:Ofast -fno-math-errno." -OPT:Ofast is described below. -OPT:alias= Specifies the pointer aliasing model to be used. By specifiying one or more of the following for , the compiler is able to make assumptions throughout the compilation: typed Assume that the code adheres to the ANSI/ISO C standard which states that two pointers of different types cannot point to the same location in memory. This is on by default when -Ofast is specified. restrict Specifies that distinct pointers are assumed to point to distinct, non-overlapping objects. This is off by default. disjoint Specifies that any two pointer expressions are assumed to point to distinct, non-overlapping objects. This is off by default. -OPT:div_split=(ON|OFF) Enable/disable changing x/y into x*(recip(y)). This is OFF by default but is enabled by -OPT:Ofast or -OPT:IEEE_arithmetic=3. -OPT:early_intrinsics=(ON|OFF) When ON, this option causes calls to intrinsics to be expanded to inline code early in the backend compilation. This may enable more vectorization opportunities if vector forms of the expanded operations exist. Default is OFF. -OPT:fast_complex=(ON|OFF) Setting fast_complex=ON enables fast calculations for values declared to be of type complex. When this is set to ON, complex absolute value (norm) and complex division use fast algorithms that are more likely to overflow or underflow than the standard algorithms. OFF is the default. fast_complex=ON is enabled if -OPT:roundoff=3 is in effect. -OPT:fast_nint=(ON|OFF) This option uses a hardware feature to implement NINT and ANINT (both single- and double-precision versions). Default is OFF but fast_nint=ON is enabled by default if -OPT:ro=3 is in effect. -OPT:goto=(OFF|ON) Disable/enable the conversion of GOTOs into higher level structures like FOR loops. The default is ON for -O2 or higher. -OPT:IEEE_arithmetic,IEEE_arith,IEEE_a=(n) specify level of conformance to IEEE 754 floating pointing roundoff/overflow behavior. n can be one of the following: 1 Adheres to IEEE accuracy. This is the default when optimization levels -O0, -O1 and -O2 are in effect. 2. May produce inexact result not conforming to IEEE 754. This is the default when -O3 is in effect. 3. All mathematically valid transformations are allowed. -OPT:IEEE_NaN_Inf=(ON|OFF) OFF specifies non-IEEE-754 results in operations that might have IEEE 754 NaN or infinity operands; this enables many optimizations which would be invalid for NaN or infinity operands. The default is ON. -OPT:Ofast Use optimizations selected to maximize performance. Although the optimizations are generally safe, they may affect floating point accuracy due to rearrangement of computations. This effectively turns on the following optimizations: -OPT:ro=2:Olimit=0:div_split=ON:alias=typed. -OPT:Olimit=(n) Disable optimization when size of program unit is > n. When n is 0, program unit size is ignored and optimization process will not be disabled due to compile time limit. The default is 0 when -Ofast is specified, otherwise the default is 6000 under -O2 and 9000 under -O3. -OPT:roundoff,ro=(n) Specifies the level of acceptable departure from source language floating-point, round-off, and overflow semantics. n can be one of the following: 0 Inhibits optimizations that might affect the floating-point behavior. This is the default when optimization levels -O0, -O1, and -O2 are in effect. 1 Allows simple transformations that might cause limited round-off or overflow differences. Compounding such transformations could have more extensive effects. This is the default level when -O3 is in effect. 2 Allows more extensive transformations, such as the reordering of reduction loops. This is the default level when -Ofast is specified. 3 Enables any mathematically valid transformation. -OPT:transform_to_memlib=(ON|OFF) When ON, this option enables transformation of loop constructs to calls to memcpy or memset. Default is ON when target processor is EM64T, OFF otherwise. -OPT:treeheight=(ON|OFF) The value ON turns on re-association in expressions to reduce the expressions' tree height. The default value is OFF. -OPT:unroll_analysis=(ON|OFF) The default value of ON lets the compiler analyze the content of the loop to determine the best unrolling parameters, instead of strictly adhering to the -OPT:unroll_times_max and -OPT:unroll_size parameters. -OPT:unroll_times_max,unroll_times=(n) Unroll inner loops by a maximum of n. The default is 4. -OPT:unroll_size=(n) Sets the ceiling of maximum number of instructions for an unrolled inner loop. If n = 0, the ceiling is disregarded. -static Suppresses dynamic linking at run-time for shared libraries; uses static linking instead. -TENV:X=(0|1|2|3|4) Specify the level of enabled exceptions that will be assumed for purposes of performing speculative code motion (default is 1 at all optimization levels). In general, an instruction will not be speculated (i.e. moved above a branch by the optimizer) unless any exceptions it might cause are disabled by this option. At level 0, no speculative code motion may be performed. At level 1, safe speculative code motion may be performed, with IEEE-754 underflow and inexact exceptions disabled. At level 2, all IEEE-754 exceptions are disabled except divide by zero. At level 3, all IEEE-754 exceptions are disabled including divide by zero. At level 4, memory exceptions may be disabled or ignored. -TENV:frame_pointer=(ON|OFF) Default is ON for C++ and OFF otherwise. Local variables in the function stack frame are addressed via the frame pointer register. Ordinarily, the compiler will replace this use of frame pointer by addressing local variables via the stack pointer when it determines that the stack pointer is fixed throughout the function invocation. This frees up the frame pointer for other purposes. Turning this flag on forces the compiler to use the frame pointer to address local variables. This flag defaults to on for C++ because the exception handling mechanism relies on the frame pointer register being used to address local variables. This flag can be turned off for C++ for programs that do not throw exceptions. -Wl,-x Passes the -x option to the linker. With this flag set, the linker will not preserve local (non-global) symbols in the output symbol table. The linker enters external and static symbols only. This option conserves space in the output file. This is OFF by default. -WOPT:aggstr=(ON|OFF) ON instructs the scalar optimizer to perform aggressive strength reduction, in which all induction expressions within a loop are replaced by temporaries that are incremented together with the loop variable. When OFF, strength reduction is only performed for non-trivial induction expressions. Turning this off sometimes can improve performance when registers are scarce. -WOPT:if_conv=(ON|OFF) Enables the translation of simple IF statements to condi- tional move instructions in the target CPU. Default is ON. -WOPT:mem_opnds=(ON|OFF) ON makes the scalar optimizer preserve any memory operands of arithmetic operations so as to help bring about subsumption of memory loads into the operands of arithmetic operations. Load subsumption is the combining of an arithmetic instruction and a memory load into one instruction. The default is OFF. -WOPT:retype_expr=(ON|OFF) ON enables the optimization in the compiler that converts 64-bit address computation to use 32-bit arithmetic as much as possible. The default is OFF. -WOPT:unroll=(0|1|2) Control the unrolling of innermost loops in the scalar optimizer. Setting to 0 suppresses this unroller. The default is 1, which makes the scalar optimizer unroll only loops that contain IF statements. Setting to 2 makes the unrolling to also apply to loop bodies that are straight line code, which duplicates the unrolling done in the code generator, and is thus unnecessary. The default setting of 1 makes this unrolling complementary to what is done in the code generator. This unrolling is not affected by the unrolling options under the -OPT group. -WOPT:val=(0|1|2) Controls the number of times the value-numbering optimization is performed in the global optimizer, with the default being 1. This optimization tries to recognize expressions that will compute identical run-time values and changes the program to avoid re-computing them. Description of the submit command MYMASK=`printf '0x%x' \$((1<<\$SPECUSERNUM))`; /usr/bin/taskset \$MYMASK $command ------------------------------------------------------------------------------------------------------------------- /usr/bin/taskset [options] [mask] [pid | command [arg] ... ] taskset is used to set or retreive the CPU affinity of a running process given its PID or to launch a new COMMAND with a given CPU affinity. The CPU affinity is represented as a bitmask, with the lowest order bit corresponding to the first logical CPU and highest order bit corresponding to the last logical CPU. When the taskset returns, it is gauranteed that the given program has been scheduled to a legal CPU. The default behaviour of taskset is to run a new command with a given affinity mask: taskset [mask] [command] [arguments] The taskset command is used in the following form in the config file: submit= MYMASK=`printf '0x%x' \$((1<<\$SPECUSERNUM))`; /usr/bin/taskset \$MYMASK $command $MYMASK is the bitmask (in hexadecimal) corresponding to a specific SPECUSERNUM. For example, $MYMASK value for the first copy of a rate run will be 0x00000001, for the second copy of the rate will be 0x00000002 etc. Thus, the first copy of the rate run will have a CPU affinity of CPU0, the second copy will have the affinity CPU1 etc. Description of the submit command 'specperl -e "system sprintf qq{start /b /wait /affinity %x %s}, (1<<$SPECUSERNUM), qq{$command}"' ------------------------------------------------------------------------------------------------------------------------------------ This command is used to bind CPUs to processes specperl -e 'script' perl command to invoke one line of script system "command" specperl starts "command" and waits for its termination. sprintf "format-string" arg1 arg2 specperl writes a string (to be used later by 'system'). The operation of sprintf is controlled by format-string. %x is conversion to hexadecimal format. %s is conversion to string (in effect, it is just appending a string) The string written by sprintf is something like /start /b /wait /affinity 4 command_to_be_executed qq qq is a double-quoted interpolated string It is a Perl way to say double quotes (") without using double quotes in a string the generated string is: system sprintf "start /b /wait /affinity %x %s",(1<<$SPECUSERNUM),"$command" where $SPECUSERNUM and $command have been (at this point) replaced by the shell. 1<<$SPECUSERNUM The number 1 is left-shifted by $SPECUSERNUM positions, yielding a mask where only bit number $SPECUSERNUM is set. (Bits are counted from right, starting with zero.) This mask is used for the affinity in the 'start' command. Description of the 'start' command used for rate runs: ------------------------------------------------------ Starts a separate window to run a specified program or command. START ["title"] [/D path] [/I] [/MIN] [/MAX] [/SEPARATE | /SHARED] [/LOW | /NORMAL | /HIGH | /REALTIME | /ABOVENORMAL | /BELOWNORMAL] [/AFFINITY ] [/WAIT] [/B] [command/program] [parameters] "title" Title to display in window title bar. path Starting directory B Start application without creating a new window. The application has ^C handling ignored. Unless the application enables ^C processing, ^Break is the only way to interrupt the application I The new environment will be the original environment passed to the cmd.exe and not the current environment. MIN Start window minimized MAX Start window maximized SEPARATE Start 16-bit Windows program in separate memory space SHARED Start 16-bit Windows program in shared memory space LOW Start application in the IDLE priority class NORMAL Start application in the NORMAL priority class HIGH Start application in the HIGH priority class REALTIME Start application in the REALTIME priority class ABOVENORMAL Start application in the ABOVENORMAL priority class BELOWNORMAL Start application in the BELOWNORMAL priority class AFFINITY The new application will have the specified processor affinity mask, expressed as a hexadecimal number. WAIT Start application and wait for it to terminate command/program If it is an internal cmd command or a batch file then the command processor is run with the /K switch to cmd.exe. This means that the window will remain after the command has been run. If it is not an internal cmd command or batch file then it is a program and will run as either a windowed application or a console application. parameters These are the parameters passed to the command/program Description of Boot options (boot.ini file): -------------------------------------------- /EXECUTE This option disables no-execute protection. See the /NOEXECUTE switch for more information. /NOEXECUTE This option is only available on 32-bit versions of Windows when running on processors supporting no-execute protection. It enables no-execute protection (also known as Data Execution Protection - DEP), which results in the Memory Manager marking pages containing data as no-execute so that they cannot be executed as code. This can be useful for preventing malicious code from exploiting buffer overflow bugs with unexpected program input in order to execute arbitrary code. No-execute protection is always enabled on 64-bit versions of Windows on processors that support no-execute protection. There are several options you can specify with this switch: /NOEXECUTE=OPTIN Enables DEP for core system images and those specified in the DEP configuration dialog. /NOEXECUTE=OPTOUT Enables DEP for all images except those specified in the DEP configuration dialog. /NOEXECUTE=ALWAYSON Enables DEP on all images. /NOEXECUTE=ALWAYSOFF Disables DEP. /NOPAE Forces Ntldr to load the non-Physical Address Extension (PAE) version of the Windows kernel, even if the system is detected as supporting x86 PAEs and has more than 4 GB of physical memory. /USEPMTIMER This switch forces the MP HAL to use the frequency-independent PMTimer, and NOT use the frequency-dependent Time Stamp Counter. Description of BIOS options: ---------------------------- DRAM Bank Interleave AUTO Interleave memory blocks across DRAM chip selects. BIOS will AUTO detect capability on each Node (Default: DISABLED) Memory Timing 1T Enable fast memory timing (Default: 2T)