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    SubjectRe: [PATCH 01/13] objtool: Rewrite hashtable sizing
    On Thu, Jun 10, 2021 at 11:14:51AM -0700, Nathan Chancellor wrote:

    > This patch as commit 25cf0d8aa2a3 ("objtool: Rewrite hashtable sizing")
    > in -tip causes a massive compile time regression with allmodconfig +
    > ThinLTO.

    Moo... the allyesconfig builds I used it on were much faster, but that
    was on regular GCC vmlinux.o after linking.

    > Adding Sami because I am not sure why this patch would have much of an impact
    > in relation to LTO. https://git.kernel.org/tip/25cf0d8aa2a3 is the patch in
    > question.
    >
    > If I can provide any further information or help debug, please let me know.
    >
    > If you are interested in reproducing this locally, you will need a
    > fairly recent LLVM stack (I used the stable release/12.x branch) and to
    > cherry-pick commit 976aac5f8829 ("kcsan: Fix debugfs initcall return
    > type") to fix an unrelated build failure. My script [2] can build a
    > self-contained toolchain fairly quickly if you cannot get one from your
    > package manager. A command like below will speed up the build a bit:

    Would something like llvm-13 from Debian be good enough?

    $ clang-13 --version
    Debian clang version 13.0.0-++20210418105309+a0898f0cecc7-1~exp1
    Target: x86_64-pc-linux-gnu
    Thread model: posix
    InstalledDir: /usr/bin

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