Re: [patch 14/14] x86_64: Choose physflat for AMD systems only when >8 CPUS.

Re: [patch 14/14] x86_64: Choose physflat for AMD systems only when >8 CPUS.

[Ashok Raj]

On Tue, Sep 06, 2005 at 01:18:08AM +0200, Andi Kleen wrote:
> On Sat, Sep 03, 2005 at 02:33:30PM -0700, akpm@osdl.org wrote:
> > 
> > From: Ashok Raj <ashok.raj@intel.com>
> > 
> > It is not required to choose the physflat mode when CPU hotplug is enabled and
> > CPUs <=8 case.  Use of genapic_flat with the mask version is capable of doing
> > the same, instead of doing the send_IPI_mask_sequence() where its a unicast.
> 
> I don't get the reasoning of this change. So probably not.

Hummm...Please see below. Nothing has changed since then, any idea why
its not acceptable now?

http://marc.theaimsgroup.com/?l=linux-kernel&m=112315304423377&w=2

This really doesnt affect me, it just bothers me to go over inefficient code.
send_IPI_mask_sequence() does unicast IPI's. When number of CPUs is <=8
the mask version acheives the same with just one write, so its a selective
broadcast which is more efficient. 

Based on our earlier exchange i assumed it was clear and apparent which is
why you  "OK"ed the version when it was submitted to -mm. 

Nothing has changed, its the exact same patch. Hope its clear now.

Entirely up to you... :-(

-- 
Cheers,
Ashok Raj
- Open Source Technology Center