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    SubjectRe: CONFIG_SMP patch updated for 2.1.61
    Hi!

    > > Here it is:
    > >
    > > ftp://ftp.shout.net/pub/users/mec/patch/config-smp.2161
    > >
    > > This updates my previous patch, config-smp-2154. There are no
    > > substantial changes.
    >
    > Note that the principal reason why CONFIG_SMP isn't an option is that it
    > affects too much. It means that if you re-make the config file,
    > _everything_ gets recompiled. It _used_ to be a config option, but I
    > removed it because of this problem.

    At least on my system, ~90% of files get recompiled when I touch
    config. (I touched it, just to measure that... You owe me 30 minutes
    of CPU time ;-)

    Only config.h:
    ls -l /usr/src/linux/target/i386/boot/zImage
    -rw-r--r-- 1 pavel users 402707 Nov 4 22:03
    /usr/src/linux/target/i386/boot/zImage
    220 files, 27 min, 5 sec
    pavel@Elf:/usr/src/linux$

    And after make clean...
    ls -l /usr/src/linux/target/i386/boot/zImage
    -rw-r--r-- 1 pavel users 402707 Nov 4 22:32
    /usr/src/linux/target/i386/boot/zImage
    255 files, 26 min, 24 sec

    So we are talking about ~30 #include's, which have nearly no impact on
    compilation time. (I did not load machine on the first time, some text
    file viewing on background...)

    > The only way I would like a CONFIG_SMP would be if the config process
    > itself was made smarter, and did:
    >
    > - separate config files (according to some simple rule). Instead of doing
    > #include <linux/config.h>
    > we'd do
    > #include <config/smp.h>
    > #include <config/scsi.h>
    > ...

    What about automatical config-dependator? In my mind there's a plan
    how to do this without forcing people to specify which config parts
    they use.

    Imagine everyone still including <linux/config.h>, but 'virtual' files
    linux/config/config_scsi_aha1770 etc. And then, when mkdep would see
    CONFIG_SCSI_AHA1770 in foo.c, it would make foo.c depend on
    CONFIG_SCSI_AHA1770. This could work.

    And I believe this could (and should) be done without mkdep.c: gcc is
    able to generate dependency information for us. (I already use
    modified makefiles from mec@shout.net, which do not need mkdep.c -
    dependency info are generated on the fly when compiling).

    > - better CONFIG_XXX sanity checking that knew about the

    ...which would not be needed if dependencies are generated automagically.

    > In short, I think that we need a more clever config setup, and before we
    > have that I don't want to see CONFIG_SMP as an option.

    Question is:

    If someone comes with system that has better config_X dependencies
    (and read-only source tree etc.), but rewrites every Makefile in
    Linux, are you going to accept that patch? Is there at least chance?

    Pavel

    --
    I'm really pavel@atrey.karlin.mff.cuni.cz. Pavel
    Look at http://atrey.karlin.mff.cuni.cz/~pavel/ ;-).

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