Linux on Power with IBM XL Compilers SPEC CPU 2006 Flags

Compilers: IBM XL C/C++ Advanced Edition for Linux V9.0 and XL Fortran Advanced Edition for Linux V11.1

Compilers: IBM XL C/C++ for Linux V10.1 and XL Fortran for Linux V12.1

Operating systems: SUSE Linux Enterprise 10, SUSE Linux Enterprise 11, and Red Hat Enterprise Linux Advanced Platform 5

Last updated: 13-Apr-2009


Selecting one of the following will take you directly to that section:

Optimization Flags

Portability Flags

Compiler Flags

Other Flags

System and Other Tuning Information

      - First we copied the original executable (baseexe) to baseexe.orig. 

      - Then, the executable is instrumented and its initial profile generated, as follows: 
        $ fdprpro -a instr baseexe 
        The output will be generated (by default) in baseexe.instr and its profile in baseexe.nprof. 

      - Next, run baseexe.instr using the training data. This will fill the profile file with information that characterizes the training workload.

      - Finally, re-run FDPR-Pro with the profile file provided, as follows: 
        $ fdprpro -a opt -f baseexe.nprof [optimization options] baseexe 

      Instrumentation Options Descriptions:
       -ei, --embedded-instrumentation
            Perform embedded instrumentation. The profile will be collected
            into global variables.

       -fd Fdesc, --file-descriptor Fdesc
            Set the file descriptor number to be used when opening the profile
            file. The default of Fdesc is set to the maximum-allowed number of
            open files.

       -imullX, --mullX-instrumentation
            perform value profiling of RA and RB operands in mullX instruc-

       -issu, --instrumentation-safe-stack-usage
            Ensure additional stack space is properly allocated for the
            instrumented run. Use this option if your application uses stack
            extensively (e.g., when the program uses alloca()). Note that this
            option adds extra overhead on instrumentation code.

       -iso offset, --instrumentation-stack-offset offset
            Set the offset from the stack, a negative number, where the
            instrumentation's area for saving registers is kept at runtime.
            Use with care.

       -M addr, --profile-map addr
            Set shared memory segment address for profiling. Alternative
            shared memory addresses are needed when the instrumented program
            application creates a conflict with the shared-memory addresses
            preserved for the profiling. Typical alternative values are
            0x40000000, 0x50000000, ... up to 0xC0000000. The default is set
            to 0x3000000.

       -[no]ri, --[no]register-instrumentation
            Instrument the input program file to collect profile information
            about indirect branches via registers. The default is set to col-
            lect the profile information.

       -[no]sfp, --[no]save-floating-point-registers
            Save floating point registers in instrumented code. The default is
            set to save floating point registers.

       Optimization Options Descriptions:

       -A alignment, --align-code alignment
            Align program so that hot code will be aligned on alignment-byte

       -abb factor, --align-basic-blocks factor
            Align basic blocks that are hotter than the average by a given
            (float) factor. This is a lower-level machine-specific alignment
            compared to --align-code. Value of -1 (the default) disables this

       -bf, --branch-folding
            Eliminate branch to branch instructions.

       -bldcg, --build-dcg
            Build a Data Connectivity Graph (DCG) for enhanced data reordering
            (applicable only with the -RD flag).

       -bp, --branch-prediction
            Set branch prediction bit for conditional branches according to
            the collected profile.

       -btcar, --branch-table-csect-anchor-removal
            Eliminate load instructions used when accessing branch tables.

       -cbtd, --convert-bss-to-data
            Convert BSS section into a data section. This is useful for more
            aggressive tocload and RD optimizations.

       -cRD, --conservativeRD
            Perform conservative static data reordering by packing together
            all frequently referenced static variables.

       -dce, --dead-code-elimination
            Eliminate instructions related to unused local variables within
            frequently executed functions. This is useful mainly after apply-
            ing function inlining optimization.

       -dp, --data-prefetch
            Insert data-cache prefetch instructions to improve data-cache per-

       -dpht threshold, --data-placement-hotness-threshold threshold
            Set data placement algorithm hotness threshold between (0,1),
            where 0 reorders the static variables in large groups based on the
            control flow, and 1 reorders the variables in very small groups
            based on their access frequency. (This is applicable only with the
            -RD flag).

       -dpnf factor, --data-placement-normalization-factor factor
            Set data placement algorithm normalization factor between (0,1),
            where 0 causes static variables to be reordered regardless of
            their size, and 1 locates only small sized variables first.
            (applicable only with the -RD flag).

       -ece, --epilog-code-eliminate
            Reduce code size by grouping common instructions in function epi-
            logs, into a single unified code.

       -fc, --function-cloning
            Enable function cloning phase only during function inlining opti-
            mizations (applicable only with function inlining flags: -i, -si,
            -ihf, -isf, -shci).

       -hr, --hco-reschedule
            Relocate instructions from frequently executed code to rarely exe-
            cuted code areas, when possible.

       -hrf factor, --hco-resched-factor factor
            Set the aggressiveness of the -hr optimization option according to
            a factor value between (0,1), where 0 is the least aggressive fac-
            tor (applicable only with the -hr option).

       -i, --inline
            Same as --selective-inline with --inline-small-funcs 12.

       -ihf pct, --inline-hot-functions pct
            Inline all function call sites to functions that have a frequency
            count greater than the given pct frequency percentage.

       -isf size, --inline-small-funcs size
            Inline all functions that are smaller than or equal to the given
            size in bytes.

       -kr, --killed-registers
            Eliminate stores and restores of registers that are killed (over-
            written) after frequently executed function calls.

       -lap, --load-address-propagation
            Eliminate load instructions of variable addresses by re-using pre-
            loaded addresses of adjacent variables.

       -las, --load-after-store
            Add NOP instructions to place each load instruction further apart
            following a store instruction that references the same memory

       -lro, --link-register-optimization
            Eliminate saves and restores of the link register in frequently-
            executed functions.

       -lu aggressiveness_factor, --loop-unroll aggressiveness_factor
            Unroll short loops containing one to several basic blocks accord-
            ing to an aggressiveness factor between (1,9), where 1 is the
            least aggressive unrolling option for very hot and short loops.

       -lun unrolling_number, --loop-unrolling-number unrolling_number
            Set the number of unrolled iterations in each unrolled loop. The
            allowed range is between (2,50). Default is set to 2. (Applicable
            only with the -lu flag).

       -nop, --nop-removal
            Remove NOP instructions from reordered code.

       -O   Switch on basic optimizations only. Same as -RC -nop -bp -bf.

       -O2  Switch on less aggressive optimization flags. Same as -O -hr -pto
            -isf 8 -tlo -kr.

       -O3  Switch on aggressive optimization flags. Same as -O2 -RD -isf 12
            -si -dp -lro -las -vro -btcar -lu 9 -rt 0 -so.

       -O4  Switch on aggressive optimization flags together with aggressive
            function inlining. Same as -O3 -sidf 50 -ihf 20 -sdp 9 -shci 90
            and -bldcg (for XCOFF files).

       -O5  Switch on aggressive optimization flags together with HLR opti-
            mization. Same as -O4 -sa -gcpyp -gcnstp -dce -vrox.

       -omullX, --mullX-optimization
            Optimize mullX instructions by adding a run-time check on RA and
            RB and performing equivalent operations with lower penalty. The
            optimization requires the use of -imullX in the instrumentation

       -pbsi, --path-based-selective-inline
            Perform selective inlining of dominant hot function calls based on
            the control flow paths leading to hot functions.

       -pc, --preserve-csects
            Preserve CSects' boundaries in reordered code.

       -pca, --propagate-constant-area
            Relocate the constant variables area to the top of the code sec-
            tion when possible.

       -pfb, --preserve-first-bb
            Preserve original location of the entry point basic block in pro-

       -pp, --preserve-functions
            Preserve functions' boundaries in reordered code.

       -[no]pr, --[no]ptrgl-r11
            Perform removal of R11 load instruction in _ptrgl csect.

       -pto, --ptrgl-optimization
            Perform optimization of indirect call instructions via registers
            by replacing them with conditional direct jumps.

       -ptoht heatness_threshold, --ptrgl-optimization-heatness-threshold
            Set the frequency threshold for indirect calls that are to be
            optimized by -pto optimization. Allowed range between 0 and 1.
            Default is set to 0.8. (Applicable only with -pto flag).

       -ptosl limit_size, --ptrgl-optimization-size-limit limit_size
            Set the limit of the number of conditional statements generated by
            -pto optimization. Allowed values are between 1 and 100. Default
            value is set to 3. (Applicable only with the -pto flag).

       -RC, --reorder-code
            Perform code reordering.

       -rcaf aggressiveness_factor, --reorder-code-aggressivenes-factor
            Set the aggressiveness of code reordering optimization. Allowed
            values are [0 1 2], where 0 preserves then original code order
            and 2 is the most aggressive. Default is set to 1. (Applicable
            only with the -RC flag).

       -rccrf reversal_factor, --reorder-code-condition-reversal-factor rever-
            Set the threshold fraction that determines when to enable condi-
            tion reversal for each conditional branch during code reordering.
            Allowed input range is between 0.0 and 1.0 where 0.0 tries to pre-
            serve original condition direction and 1.0 ignores it. Default is
            set to 0.8 (Applicable only with the -RC flag).

       -rcctf termination_factor, --reorder-code-chain-termination-factor ter-
            Set the threshold fraction that determines when to terminate each
            chain of basic blocks during code reordering. Allowed input range
            is between 0.0 and 1.0 where 0.0 generates long chains and 1.0
            creates single basic block chains. Default is set to 0.05. (Appli-
            cable only with the -RC flag).

       -RD, --reorder-data
            Perform static data reordering.

       -rmte, --remove-multiple-toc-entries
            Remove multiple TOC entries pointing to the same location in the
            input program file.

       -rt removal_factor, --reduce-toc removal_factor
            Perform removal of TOC entries according to a removal factor
            between (0,1), where 0 removes non-accessed TOC entries only and 1
            removes all possible TOC entries.

       -rtb, --remove-traceback-tables
            Remove traceback tables in reordered code.

       -sdp aggressiveness_factor, --stride-data-prefetch aggressiveness_fac-
            Perform data prefetching within frequently executed loops based on
            stride analysis, according to an aggressiveness factor between
            (1,9), where 1 is the least aggressive.

       -sdpla iterations_number, --stride-data-prefetch-look-ahead itera-
            Set the number of iterations for which data is prefetched into the
            cache ahead of time. Default value is set to 4 iterations. (Appli-
            cable only with the -sdp flag).

       -sdpms stride_min_size, --stride-data-prefetch-min-size stride_min_size
            Set the minimal stride size in bytes, for which data will be con-
            sidered a candidate for prefetching. Default value is set to 128
            bytes. (Applicable only with the -sdp flag).

       -see level
            Use simplified prolog/epilog for functions that perform condi-
            tional early-exit. Use basic optimization with level=0 and maximal
            with level=1.

       -shci pct, --selective-hot-code-inline pct
            Perform selective inlining of functions in order to decrease the
            total number of execution counts, so that only functions with hot-
            ness above the given percentage are inlined.

       -si, --selective-inline
            Perform selective inlining of dominant hot function calls.

       -sidf percentage_factor, --selective-inline-dominant-factor percent-
            Set a dominant factor percentage for selective inline optimiza-
            tion. The allowed range is between 0 and 100. Default is set to
            80. (Applicable only with the -si and -pbsi flags).

       -siht frequency_factor, --selective-inline-hotness-threshold fre-
            Set a hotness threshold factor percentage for selective inline
            optimization to inline all dominant function calls that have a
            frequency count greater than the given frequency percentage.
            Default is set to 100. (Applicable only with the -si -pbsi flags).

       -slbp, --spinlock-branch-prediction
            Perform branch prediction bit setting for conditional branches in
            spinlock code containing l*arx and st*cx instructions. (Applicable
            after -bp flag).

       -sldp, --spinlock-data-prefetch
            Perform data prefetching for memory access instructions preceding
            spinlock code containing l*arx and st*cx instructions.

       -sll Lib1:Prof1,...,LibN:ProfN, --static-link-libraries
            Statically link hot code from specified dynamically linked
            libraries to the input program. The parameter consists of a comma-
            separated list of libraries and their profiles. IMPORTANT: Licens-
            ing rights of specified libraries should be observed when applying
            this copying optimization.

       -sllht hotness_threshold, --static-link-libraries-hotness-threshold
            Set hotness threshold for the --static-link-libraries optimiza-
            tion. The allowed input range is between 0 (least aggressive) and
            1, or -1, which does not require a profile and selects all code
            that might be called by the input program from the given
            libraries. Default is set at 0.5.

       -so, --stack-optimization
            Reduce the stack frame size of functions that are called with a
            small number of arguments.

       -spc, --shortcut-plt-calls
            Shortcut PLT calls in shared libraries to local functions if they
            exist. Note: Resolving to external symbols is disabled for such

       -stf, --stack-flattening
            Merge the stack frames of inlined functions with the frames of the
            calling functions.

       -tb, --preserve-traceback-tables
            Force the restructuring of traceback tables in reordered code. If
            -tb option is omitted, traceback tables are automatically included
            only for C++ applications that use the Try & Catch mechanism.

       -tlo, --tocload-optimization
            Replace each load instruction that references the TOC with a cor-
            responding add-immediate instruction via the TOC anchor register,
            where possible.

       -ucde, --unreachable-code-data-elimination
            Remove unreachable code and non-accessed static data.

       -vro, --volatile-registers-optimization
            Eliminate stores and restores of non-volatile registers in fre-
            quently executed functions by using available volatile registers.

       -vrox, --volatile-registers-extended-optimization
            Eliminate stores and restores of non-volatile registers in fre-
            quently executed functions by using available volatile registers,
            the extended version supports FP registers and transparency.

       General Options:

       -h, --help
            Print online help.

       -m machine-model, --machine machine-model
            Generate code for the specified machine model. Target machine can be one of the following models: power2, power3, ppc405, ppc440,
            power4, ppc970, power5, power6, ppe, spe, spe_edp, z10, z9. Default is set to no machine.

       -q, --quiet
            Set quiet output mode, suppressing informational messages.

       -st stat_file, --statistics stat_file
            Output statistics information to stat_file. If stat_file is '-', the output goes to standard output. See --verbose for the default.

       -v level, --verbose level
            Set verbose output mode level. When set, various statistics about the target optimized program are printed into the file pro-
            gram.stat. Allowed level range is between 0 and 3. Default is set to 0.

       -V, --version
            Print version.