lkml.org 
[lkml]   [2008]   [Feb]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86: X86_HT always enable on X86_64 SMP
On Wed, Feb 27, 2008 at 02:16:56PM -0800, Hiroshi Shimamoto wrote:
> Adrian Bunk wrote:
> > On Wed, Feb 27, 2008 at 01:30:59PM -0800, H. Peter Anvin wrote:
> >> Adrian Bunk wrote:
> >>> On Wed, Feb 27, 2008 at 01:16:30PM -0800, Hiroshi Shimamoto wrote:
> >>>> From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
> >>>>
> >>>> X86_HT is used for hyperthreading or multicore on 32-bit.
> >>>> The X86_HT on 64-bit is different from 32-bit, it means hyperthreading only.
> >>>> And X86_HT is not used on 64-bit except from cpu/initel_cacheinfo.c.
> >>>>
> >>>> Unify X86_HT for hyperthreading or multicore.
> >>>> Turn X86_HT on when X86_64 and SMP are enabled.
> >>> Please fix it properly instead - fiddling around with it the way you do
> >>> only asks for trouble in the future.
> >>>
> >>> What we need are two different variables for:
> >>> - hyperthreading and
> >>> - multicore
> >> He does, and calls them SCHED_SMT and SCHED_MC respectively.
> >
> > These are the already existing scheduler related variables that are
> > only a part of the X86_HT usages.
> >
> >> It's not particularly clear to me what X86_HT is meant to be used for
> >> anymore at all.
> >
> > grep through the source code and you find it is sometimes used for
> > hyperthreading and sometimes for multicore.
> >
> > I don't care whether X86_HT gets splitted or perhaps even removed, but
> > any change to it should remove the status quo of it having two different
> > semantics.
>
> OK, you say "Don't mix two different semantics into one variable X86_HT", right?

Exactly.

This mixing is not your fault since it's an older problem, but instead
of your suggested patch we should fix it properly.

> Thanks,
> Hiroshi Shimamoto

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed



\
 
 \ /
  Last update: 2008-02-27 23:41    [W:0.047 / U:0.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site