Re: [PATCH] Skip tsc synchronization checks if CONSTANT_TSC bit is set.

[Andi Kleen <andi@firstfloor.org>]

> BIOSes are also just software, and we have to deal with bugs in them 
> *all the time*.  The reality is that we're going to have to deal with 
> both vendor and user reluctance to upgrade, and therefore have to deal 
> with brokenness in the field. 

In the field they will just continue using clock=pit, like they
always did on vmware. And also they will not update the Linux kernel.

This is strictly for new installations. And I frankly don't 
see why Linux needs to get white listed workarounds when the 
Hypervisor couldn't as well be fixed. We have the bizarre
situation here where a HV vendor tries to add workarounds
to Linux instead of fixing it on their products.

Now making generic code a little more flexible in what
it accepts is fine though (like relaxing tsc_sync or 
checking and trusting UNSTABLE_TSC). That will scale at least
and doesn't need significant new code.

-Andi