Re: [realtime] Re: [rtl] RTAI experiences, or: The Cathedral and the Baazar, part #2

[yodaiken@fsmlabs.com]

On Mon, Dec 20, 1999 at 04:42:56PM +0000, Stuart Hughes wrote:
> yodaiken@fsmlabs.com wrote:
> 
> [snip]
> > 
> > See hrtime_t clock_gethrtime(clockid_t clock)
> > and
> > pthread_make_periodic_np
> > 
> > Any problems with those?
> 
> Yes, pthead_make_periodic_np is not in any POSIX standard.  For those
> wishing to make their code portable, which is the primary purpose of
> using a POSIX API, any calls suffixed _np will destroy this possibility. 

I must have misread your earlier comment which I thought asked for
 a nanosecond interface to clocks on the V1API.  The pthread_make_periodic
is intended to export the V1 simple functionality to V2 while replacing
"ticks" with nanoseconds. 


> IMHO, it would be better to stick with standard POSIX and use POSIX
> clocks for timing.  If this is too painful to users or people do not
> want to use POSIX, the original NMT/RTAI API provides a simple
> alternative.

As you noted, the V1 RTLinux API has an unpleasant dependency on the 8253
timer.  One of the reasons that we went to the V2 API is that we did not
see a clean way of repairing the defects in  V1.

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