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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linuxppc-dev@ozlabs.org, cbe-oss-dev@ozlabs.org
Subject: Re: [Cbe-oss-dev] [RFC, PATCH] selection of CPU optimization
Date: Fri, 13 Apr 2007 20:43:02 +0200	[thread overview]
Message-ID: <00df01c80b8b5153a04a7cbe0bc727f2@kernel.crashing.org> (raw)
In-Reply-To: <200704130210.48508.arnd@arndb.de>

> My understanding at this point is that we can always fall back
> to -mcpu=powerpc or -mcpu=powerpc64,

Yes.  With perhaps and added -mno-string or similar if
some supported CPU really needs it.


>  and also

[SNIP]

> So if we select e.g. power6 and cell, it needs to fall back to power4,
> which is the common subset. Selecting both 403 and 405 would result
> in falling back to -mcpu=powerpc, because they don't have any larger
> subset.

This is way complicated.  Also, it is not unique to the
kernel; you'd be better off adding this logic to the
compiler itself.  OTOH, it's such a niche market, maybe
the distros that want it (if any do) should do this in
their RPM build scripts or similar.


Segher

      parent reply	other threads:[~2007-04-13 18:43 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-10 11:15 [patch 3/3] cell: prevent alignment interrupt on local store Akinobu Mita
2007-04-10 12:52 ` Segher Boessenkool
2007-04-11  3:06   ` Akinobu Mita
2007-04-10 21:22 ` Benjamin Herrenschmidt
2007-04-11  2:56   ` Akinobu Mita
2007-04-11  3:30     ` Benjamin Herrenschmidt
2007-04-11 21:03       ` Segher Boessenkool
2007-04-12  4:23         ` Olaf Hering
2007-04-12  5:26           ` Benjamin Herrenschmidt
2007-04-12  6:33             ` Olaf Hering
2007-04-12  6:38               ` Benjamin Herrenschmidt
2007-04-12  8:31                 ` Gabriel Paubert
2007-04-12  8:48                   ` Benjamin Herrenschmidt
2007-04-12  6:50           ` Segher Boessenkool
2007-04-12  6:57             ` [Cbe-oss-dev] " Michael Ellerman
2007-04-12  7:07               ` Segher Boessenkool
2007-04-12 18:43           ` Arnd Bergmann
2007-04-12 18:55             ` Arnd Bergmann
2007-04-12 19:57               ` Segher Boessenkool
2007-04-12 19:52             ` Segher Boessenkool
2007-04-12 13:01   ` [RFC, PATCH] selection of CPU optimization Arnd Bergmann
2007-04-12 16:45     ` Kumar Gala
2007-04-12 17:26       ` [Cbe-oss-dev] " Arnd Bergmann
2007-04-12 18:17         ` Kumar Gala
2007-04-12 19:25           ` Arnd Bergmann
2007-04-12 20:04           ` Olof Johansson
2007-04-12 20:01             ` Segher Boessenkool
2007-04-12 20:22               ` Olof Johansson
2007-04-12 20:22                 ` Segher Boessenkool
2007-04-12 19:50         ` Segher Boessenkool
2007-04-13  0:10           ` Arnd Bergmann
2007-04-13  2:03             ` Olof Johansson
2007-04-13 18:43             ` Segher Boessenkool [this message]

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