Re: IA64 implementation of timesource for new time of day subsystem

Christoph Lameter
2005-05-16T22:03:12Z

On Mon, 16 May 2005, john stultz wrote:

> Since its possible to do jitter compensation within the itc timesource
> driver (and within the fastcall code to preserve the existing
> performance), would it be reasonable to deffer making the jitter
> compensation code generic until another timesource needs it? It should
> be a fairly simple change.

Well looks that we will start out with the new time subsystem by putting
some hacks in. I need to check in the funky routine (for setting up the
fastcall configuration) if the function pointer passed == jitter-compensated-itc
and depending on that set a special flag that makes the asm code do jitter
compensation.

> Or is this just something I'm being hard-headed about?

Looks like it. Its not that difficult. Add a jitter compensation flag to
timesource. Check on retrieving from a timesource if its less than last if
flag is set. Pass the field to the funky function to setup the
vsyscalls.

Maybe add a general flags field? There may be other things that need to be
added in the future.