TSC Timecounter and multi-core/SMP

[Daniel O'Connor]

On Fri, 18 Apr 2008, Julian Elischer wrote:
> David O'Brien wrote:
> > The TSC on K8 is not invariant - its rate of change is affected by
> > P-state changes.
> >
> > The TSC on Greyhound (Family 10h) is invariant.
> > [but as stated above, is not synced with other cores]
>
> You'd think that an invariant sync'd clock (fast to read) of some
> type would have been done by someone by now.. The software people
> have been asking for this for the last decade at least.

Probably because it's very very difficult to get right :)	

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C