Make timestamp implementation choice available for the CPU port

[Sebastian Huber]

In "score/include/rtems/score/timestamp.h" we have:

/*

• NOTE: Eventually each port should select what it should use!!! *
• These control which implementation of SuperCore? Timestamp is used. *
• if defined(CPU_RTEMS_SCORE_TIMESTAMP_IS_STRUCT_SPEC)
• struct timespec is used
• else if defined(CPU_RTEMS_SCORE_TIMESTAMP_IS_INT64)
• int64_t is used *
• When int64_t is used, then
• if defined(CPU_RTEMS_SCORE_TIMESTAMP_INT64_INLINE)
• the methods are inlined
• else
• the methods are NOT inlined *
• Performance of int64_t versus struct timespec
• ============================================= *
• On PowerPC/psim, inlined int64_t saves ~50 instructions on each
• _Thread_Dispatch operation which results in a context switch.
• This works out to be about 10% faster dispatches and 7.5% faster
• blocking semaphore obtains. The following numbers are in instructions
• and from tm02 and tm26. *
• timespec int64 inlined int64
• dispatch: 446 446 400
• blocking sem obtain: 627 626 581 *
• On SPARC/sis, inlined int64_t shows the same percentage gains.
• The following numbers are in microseconds and from tm02 and tm26. *
• timespec int64 inlined int64
• dispatch: 59 61 53
• blocking sem obtain: 98 100 92 *
• Inlining appears to have a tendency to increase the size of
• some executables.
• Not inlining reduces the execution improvement but does not seem to
• be an improvement on the PowerPC and SPARC. The struct timespec
• and the executables with int64 not inlined are about the same size. *
• Once there has some analysis of which algorithm and configuration
• is best suited to each target, these defines should be moved to
• the appropriate score/cpu cpu.h file. In the meantime, it is
• appropriate to select an implementation here using CPU macros. */

#define CPU_RTEMS_SCORE_TIMESTAMP_IS_STRUCT_SPEC
/*
#define CPU_RTEMS_SCORE_TIMESTAMP_IS_INT64
#define CPU_RTEMS_SCORE_TIMESTAMP_INT64_INLINE
*/

I think it is time to delegate the implementation choice to the CPU port (cpu.h).

I propose to change the defines a bit to be more in line with the other CPU defines. In cpu.h we have to define:

#define CPU_TIMESTAMP_USE_STRUCT_TIMESPEC TRUE

or

#define CPU_TIMESTAMP_USE_INT64 TRUE

or

#define CPU_TIMESTAMP_USE_INT64_INLINE TRUE

[Sebastian Huber]

Template for cpu.h

[Sebastian Huber]

Committed to CVS head.

[Gedare Bloom]

Replace Version=HEAD with Version=4.11 for the tickets with Milestone >= 4.11