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

From: James Courtier-Dutton <James_at_superbug.co.uk>
Date: 2005-05-15 20:22:27
Christoph Lameter wrote:
> On Fri, 13 May 2005, john stultz wrote:
> 
> 
>>I look forward to your comments and feedback.
> 
> 
> Here is the implementation of the IA64 timesources for the new time of 
> day subsystem.
> 
> This is quite straighforward. Thanks John. However, the ITC
> interpolator can no longer use MMIO in SMP situations since there is no 
> provision for jitter compensation in the new time of day subsystem. I have
> implemented that via a function now which will slow down clock access
> for non SGI IA64 hardware significantly since it will not be able to use
> the fastcall anymore.
> 
> I am working on the fastcall but I would need a couple of changes
> to the core code to make the following symbols non-static since they
> will need to be accessed from the fast syscall handler:
> 
> timesource
> system_time
> wall_time_offset
> offset_base
> 

Will this mean that Linux will have a monotonic time source?
For media players we need a timesource that does not change under any
circumstances. e.g. User changes the clock time, the monotonic time
source should not change. The monotonic time source should just start at
0 at power on, and continually increase accurately over time. I.e. A
very accurate "uptime" measurement.

James
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Received on Sun May 15 05:12:19 2005

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