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Descriptions of options used by HP for CPU2000:
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+A Cause the linker ld(1) to use only archive libraries
for all occurrences of the -l option. Also inform the
C++ run-time environment that no shared libraries will
be used by the program.
-Ae Enable ANSI compatibility mode with UNIX extensions.
-D Set definition for preprocessor.
+DA<arch> Generate code for the architecture specified.
+DS<arch> Schedule code for the architecture specified.
+ESfic Replace millicode calls with in-line code for
for indirect calls.
+ESlit Put literals in read-only text space.
fastmem.o Replacement for malloc/free that assumes ANSI compliant code.
+I/+P Optimize/Instrument for profile based optimization.
-K Use static storage for locals instead of stack storage. Same
functionality as the +save option. The default is +nosave.
Kernel Tunables (Listed separately)
+O1 Perform optimizations within basic blocks only.
+O2 Perform +O1 optimizations. In addition perform global
optimizations at the procedure level. (Same as -O.)
+O3 Perform +O2 optimizations as well as interprocedural global
optimizations within a file (including inlining).
+O4 Perform +O3 optimizations. Also apply interprocedural
optimizations across all files of the program.
+Oaggressive Apply aggressive optimizations which include scheduling on
procedure entry and exit code, replacing standard library
calls with inlined code sequences, no auto-initialization
of uninitialized local scalar non-static variables, and
scheduling beyond basic block boundaries.
+Oall Apply all optimizations that would be enabled by specifying
+O4, +Oaggressive, and +Onolimit on the same command line.
Detailed options countermanding components of +Oall override
that component.
+Ocachepadcommon
Pad common blocks to avoid cache collisions.
+Odataprefetch Generate data prefetch instructions for data structures
referenced within innermost loops.
+Oentrysched Perform instruction scheduling on a subprogram's entry and
exit sequences.
+O[no]fastaccess
Enable [disable] fast access to global data items.
+O[no]fltacc Disable [enable] optimizations that cause imprecise
floating-point results.
+Oinlinebudget=n
The +Oinlinebudget option controls the
aggressiveness of inlining. n is an integer in
the range 1 - 1000000 that specifies the level
of aggressiveness as follows:
n Meaning
= 100 Default level on inlining.
> 100 More aggressive inlining.
2 - 99 Less aggressive inlining.
= 1 Only inline if it reduces code
size.
This optimization can occur at optimization
levels 3, and 4. The default is +Oinlinebudget=100.
+O[no]libcalls Invoke [do not invoke] low call-overhead versions of
select library routines.
+O[no]limit Suppress [do not suppress] optimizations that
significantly increase compile-time or consume
enormous amounts of memory. These optimizations
can occur at levels 2, 3, and 4. The default is +Olimit.
+O[no]loop_block
Enable [disable] loopblocking for data cache optimizations.
Available at optimization level 3 and above.
+O[no]loop_unroll
Enable [disable] loop unrolling.
+Omultiprocessor
Prevent instruction cache prefetching following subroutine
returns. This can benefit some multithreaded applications.
+noeh Disable exception handling. Note that mixing objects
compiled both with and without +noeh can have undesired
results. Object destruction, for example, will not be
done for objects local to functions compiled with the
+noeh option.
+O[no]promote_indirect_calls
Enable [disable] the promotion of indirect calls
to direct calls. (Indirect calls occur with
pointers to functions (and virtual calls for
C++).) This option can be used at optimization
levels 3 and 4. The default is
+Onopromote_indirect_calls.
+Optrs_strongly_typed
Assume that all pointers are type safe.
+O[no]ptrs_to_globals
Optimize with assumption that global variables
may [may not] be modified through pointers.
+Oregionsched Perform scheduling across branches.
+Ostaticprediction
Enable static branch prediction.
+O[no]vectorize Replace eligible loops with calls to the vector library.
+Owhole_program_mode
Hold global variables in registers longer and delete
inlined or cloned global procedures.
-Wl,+FPD Enable sudden underflow (flush to zero) of denormalized
values.
-Wl,-a,archive Link with archive format libraries rather than shared.
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Descriptions of Kernel Tunables
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dbc_max_pct Maximum dynamic buffer cache size as a percent of system memory
dbc_min_pct Minimum dynamic buffer cache size as a percent of system memory
vps_ceiling Maximum System-Selected Page Size (in Kbytes)
vps_pagesize Default user page size (in Kbytes)