From: Adrian Bunk <bunk@fs.tum.de>
To: Robert Schwebel <robert@schwebel.de>
Cc: "Richard B. Johnson" <root@chaos.analogic.com>,
Juergen Beisert <jbeisert@eurodsn.de>,
cliff white <cliffw@osdl.org>,
piggin@cyberone.com.au, mpm@selenic.com,
linux-kernel@vger.kernel.org
Subject: Re: [1/4] better i386 CPU selection
Date: Tue, 20 Jan 2004 23:10:25 +0100 [thread overview]
Message-ID: <20040120221025.GI12027@fs.tum.de> (raw)
In-Reply-To: <20040117091337.GZ5139@pengutronix.de>
On Sat, Jan 17, 2004 at 10:13:37AM +0100, Robert Schwebel wrote:
> Hi,
Hi Robert,
> On Sat, Jan 17, 2004 at 03:15:32AM +0100, Adrian Bunk wrote:
> > Besides the AMD Elan cpufreq driver I see nothing where CONFIG_MELAN
> > gave you any real difference (except your highest goal is to avoid a
> > recompilation when switching from the Pentium 4 to the AMD Elan - but I
> > doubt the really "prevents development").
> >
> > But I'm not religious about this issue. Let Robert decide, the Elan
> > support is his child.
> >
> > > > > - added optimizing CFLAGS for the AMD Elan
> > >
> > > There are no such different "optimizations" for ELAN.
> >
> > What's wrong wih the -march=i486 Robert suggested?
>
> I've not followed the 2.6 development regarding the arch selection that
> closely; let's collect arguments:
>
> - Is it still possible to run a -march=i486 built kernel on a pentium?
> IMHO It would be good to optimize the code for i486, but I'm not that
> familiar with how good gcc optimizes for 486 that I can comment this.
yes, since a Pentium supports a superset of the 486 gcc can't optimize
for a 486 in a way that the code won't run on a Pentium.
> - I personally work with lots of cross architectures like ARM, so cross
> compiling for an embedded system is no problem for me. But if people
> want to test stuff on their pentiums I also have no problem with that.
>
> Other arguments?
The only reason why I sent the patch to make the AMD Elan a separate
subarch was the CLOCK_TICK_RATE #ifdef in include/asm-i386/timex.h .
It should be possible to change it to a variable (as with
CONFIG_X86_PC9800) if both the Elan and a different cpu are supported if
this is really a required use.
If this is the solution you prefer, how would you do runtime detection
for the AMD Elan?
> Robert
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
next prev parent reply other threads:[~2004-01-20 22:12 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-06 5:48 2.6.1-rc1-tiny2 Matt Mackall
2004-01-06 6:33 ` 2.6.1-rc1-tiny2 Nick Piggin
2004-01-06 6:46 ` 2.6.1-rc1-tiny2 Matt Mackall
2004-01-06 7:08 ` 2.6.1-rc1-tiny2 Nick Piggin
2004-01-10 0:46 ` 2.6.1-rc1-tiny2 Adrian Bunk
2004-01-10 0:50 ` [0/4] better i386 CPU selection Adrian Bunk
2004-01-10 0:52 ` [1/4] " Adrian Bunk
2004-01-10 11:04 ` Wichert Akkerman
2004-01-11 3:13 ` Adrian Bunk
2004-01-14 20:49 ` [-mm patch] " Adrian Bunk
2004-01-16 19:15 ` [1/4] " cliff white
2004-01-16 19:32 ` Richard B. Johnson
2004-01-17 0:01 ` Andrew Morton
2004-01-17 2:57 ` Adrian Bunk
2004-01-19 15:14 ` John Stoffel
2004-01-19 23:42 ` Nick Piggin
2004-01-17 2:15 ` Adrian Bunk
2004-01-17 9:13 ` Robert Schwebel
2004-01-20 22:10 ` Adrian Bunk [this message]
2004-01-20 22:31 ` Richard B. Johnson
2004-01-20 22:47 ` George Anzinger
2004-01-17 10:01 ` aeriksson
2004-01-10 0:57 ` [2/4] move "struct movsl_mask movsl_mask" to usercopy.c Adrian Bunk
2004-01-10 0:57 ` [3/4] proof of concept: make arch/i386/kernel/cpu/Makefile CPU specific Adrian Bunk
2004-01-10 0:58 ` [4/4] proof of concept: make arch/i386/kernel/cpu/mtrr/Makefile " Adrian Bunk
2004-01-10 22:14 ` 2.6.1-rc1-tiny2 Matt Mackall
2004-01-12 2:20 ` 2.6.1-rc1-tiny2 Nick Piggin
2004-01-07 14:06 ` 2.6.1-rc1-tiny2 Jens Axboe
2004-01-07 18:50 ` 2.6.1-rc1-tiny2 Matt Mackall
2004-01-07 19:27 ` 2.6.1-rc1-tiny2 Mitchell Blank Jr
2004-01-07 20:10 ` 2.6.1-rc1-tiny2 Matt Mackall
2004-01-07 21:41 ` 2.6.1-rc1-tiny2 Trond Myklebust
2004-01-07 21:10 ` 2.6.1-rc1-tiny2 Jens Axboe
2004-01-07 21:30 ` 2.6.1-rc1-tiny2 Matt Mackall
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