Re: [PATCH -tip, final] perf, x86: Add hw_watchdog_set_attr() in a sake of nmi-watchdog on P4

[Don Zickus <dzickus@redhat.com>]

On Tue, Jul 05, 2011 at 01:44:37PM +0200, Ingo Molnar wrote:
> > Probably I miss something and you mean something completely different?
> 
> What i am missing is that you have not pointed out the *core problem* 
> you are fixing and it's not obvious from the changelog either!

Cyril,

I think you didn't explain the fact that without this patch if you enable
nmi_watchdog, then the 'perf' tool doesn't work on a P4.  This is bad for
end users.  It seems like with all the P4 register coupling an end user
can run either the nmi_watchdog _or_ perf but not both.

For RHEL-6 this was bad because we like to enable the nmi_watchdog.

This patch does some magic and allows the end user to use the nmi_watchdog
_and_ perf concurrently (a common expected behaviour).

I hope that clears things up Ingo.

Cheers,
Don