Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata

From: Chris Meadors (twrchris_at_hereintown.net)
Date: 09/15/03

  • Next message: Dmitri Katchalov: "Re: 2.6.0-test5 atkbd.c: Unknown key (100% reproduceable)" 
    To: linux-kernel@vger.kernel.org
Date:	15 Sep 2003 09:46:04 -0400

    On Mon, 2003-09-15 at 08:38, Nick Piggin wrote:

    > OK, the reason why I don't like the sound of this is because the size
    > of your option set has now been squared, and its no longer "make these
    > CPUs work".

    The way I see the config option working is, having a sub-menu that says
    something like, "Select the CPU the kernel will be run on." From there
    you can pick one CPU. This sets the in kernel optimizations for that
    CPU, along with the work arounds (obviously). It also sets the compiler
    flags for the padding, and "-march=[CPU]". Then in a sub-menu of this
    menu, there is an "Advanced processor selection". The help text would
    be something like, "In addition to the primary processor selected above,
    also allow this kernel to be booted on the processors selected below.
    Selecting this option disables some of the optimizations for the primary
    processor." Just turning on that option would change the "-march=" to
    "-mcpu=". Then in the menu one could select from any of the CPUs
    listed. Each one would enable the work around code to allow the built
    kernel to run correctly on a machine with a different CPU.

    I see this as sort of like the advanced partition selection, or the
    compiled in fonts.

    > I can see an argument for cache line size but thats about it. I can't
    > think of my optimisations that should be done on one architecture but
    > not another.

    Don't forget the compiler optimization flags. A kernel built with
    "-march" may not run on any other CPUs. 

    -- 
Chris
-
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/
  • Next message: Dmitri Katchalov: "Re: 2.6.0-test5 atkbd.c: Unknown key (100% reproduceable)"

    Relevant Pages