DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:in-reply-to:references:from:date:message-id:subject:to
         :cc:content-type:content-transfer-encoding;
        b=jbuQSR2k6xwDP9OJ2LgsLcevyyOu1nLc7f27PIlBykETxHQFlP/1zG9uKLiNIoAXo+
         LkZyuEk4AGbTHdjNxpQjeYnS6FY5ev3jEpcYklXL0D26wgfF1qTB0inz35Z44sp8m/XB
         Yp7OvqZ11tlqiUQOjZ67EBwpXqZxNIzibAqSU=
MIME-Version: 1.0
In-Reply-To: <20091109201608.GD15159@caffeine.csclub.uwaterloo.ca>
References: <40101cc30910021912r17b3a08bue1b9412e4fa47d89@mail.gmail.com> 
	<20091003072127.GC21407@elte.hu> <40101cc30911060659k7b3b6428ob1340e476bdbac5b@mail.gmail.com> 
	<4AF4526B.4060101@zytor.com> <40101cc30911081042n93e268bs66b9436a0174a19a@mail.gmail.com> 
	<20091109201608.GD15159@caffeine.csclub.uwaterloo.ca>
From: Matteo Croce <technoboy85@gmail.com>
Date: Mon, 9 Nov 2009 22:03:35 +0100
Message-ID: <40101cc30911091303v23b0d336u982ce70be4a0b66e@mail.gmail.com>
Subject: Re: i686 quirk for AMD Geode
To: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2613
Lines: 69

On Mon, Nov 9, 2009 at 9:16 PM, Lennart Sorensen
<lsorense@csclub.uwaterloo.ca> wrote:
> On Sun, Nov 08, 2009 at 07:42:48PM +0100, Matteo Croce wrote:
>> There is a small advantage, but considering that GCC isn't much geode aware yet
>> there is stil room for improvement IMHO:
>
> Perhaps gcc considers geode to mean geode GX[m12] not geode LX (which is
> newer and the one in question here).
>
> The Geode GX line prefers i486 code to i586 code (which appears to be
> what -march=geode is for). ?I am using i486 at the moment when I build
> for this one.
>
> The Geode LX is what is being discussed which is in fact mostly a K6 as
> far as I understand things. ?It seems to like i686 code, other than
> apparently those NOP instructions. ?I wonder if the K6 has those noop
> instructions and if not, perhaps gcc 4.4's -march=k6-3 would be the
> right choice. ?I have always suspected the LX was really a K6-3 based
> design (the cache sizes are a bit different, but clock speeds and
> instruction sets seem to match).
>
> The Geode NX (which no one has mentioned yet) is an Athlon derived chip.
>
>> root@alix:/usr/src/dist# ll
>> totale 257M
>> -rwxr-xr-x 1 1000 src ?93K ?8 nov ?2009 bzip2-i586
>> -rwxr-xr-x 1 1000 src ?93K ?8 nov ?2009 bzip2-i686
>> -rwxr-xr-x 1 1000 src ?60K ?8 nov ?2009 gzip-i586
>> -rwxr-xr-x 1 1000 src ?60K ?8 nov ?2009 gzip-i686
>> -rw-r--r-- 1 1000 src 256M ?8 nov ?2009 linux-2.6.31.5.tar
>> -rwxr-xr-x 1 1000 src ?90K ?8 nov ?2009 lzma-i586
>> -rwxr-xr-x 1 1000 src ?94K ?8 nov ?2009 lzma-i686
>> root@alix:/usr/src/dist# time cat linux-2.6.31.5.tar >/dev/null
>>
>> real ? ?0m10.168s
>> user ? ?0m0.030s
>> sys ? ? 0m1.390s
>> root@alix:/usr/src/dist# time ./gzip-i586 -9 < linux-2.6.31.5.tar >/dev/null
>>
>> real ? ?5m22.331s
>> user ? ?5m10.820s
>> sys ? ? 0m11.170s
>> root@alix:/usr/src/dist# time ./gzip-i686 -9 < linux-2.6.31.5.tar >/dev/null
>>
>> real ? ?5m3.737s
>> user ? ?4m51.880s
>> sys ? ? 0m11.510s
>> root@alix:/usr/src/dist# time ./bzip2-i586 -9 < linux-2.6.31.5.tar >/dev/null
>>
>> real ? ?9m16.539s
>> user ? ?9m4.410s
>> sys ? ? 0m11.760s
>> root@alix:/usr/src/dist# time ./bzip2-i686 -9 < linux-2.6.31.5.tar >/dev/null
>>
>> real ? ?8m48.682s
>> user ? ?8m34.950s
>> sys ? ? 0m13.260s
>
> --
> Len Sorensen
>

You're right, indeed this is being discussed here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41989
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/