x86-64: Syncing dualcore cpus TSCs

Hi,

This might be a very bad suggestion, but here it is:

On dualcore cpus (amd64) the TSC will get out of sync when executing hlt 
instruction.
booting with idle=poll, will make it never to execute hlt, hence TSC will be in 
sync.
booting with notsc will make it use other time source...but this is slower
  (this is default after "[PATCH] x86-64: Fix bad assumption that dualcore cpus 
have synced TSCs")

How about syncing TSC after hlt?

If cost of syncing TSC's is smaller than cost of using other time source this 
might be an alternative.

/Jonas