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From:   =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>
To:     Conor Dooley <conor@kernel.org>,
        Palmer Dabbelt <palmer@dabbelt.com>
Cc:     ndesaulniers@google.com, jszhang@kernel.org, llvm@lists.linux.dev,
        Paul Walmsley <paul.walmsley@sifive.com>,
        aou@eecs.berkeley.edu, Arnd Bergmann <arnd@arndb.de>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-arch@vger.kernel.org
Subject: Re: [PATCH v2 0/4] riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
In-Reply-To: <20230621-hungrily-pancake-9e1ff5b0b02a@spud>
References: <mhng-8caf7779-aa9e-496a-b2ee-2e6d6d1d76ff@palmer-ri-x1c9a>
 <mhng-861ea8a6-c92c-4a78-a1a6-dfb4df554aee@palmer-ri-x1c9a>
 <20230621-hungrily-pancake-9e1ff5b0b02a@spud>
Date:   Wed, 21 Jun 2023 19:51:15 +0200
Message-ID: <87wmzwn1po.fsf@all.your.base.are.belong.to.us>
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Conor Dooley <conor@kernel.org> writes:

[...]

>> So I'm no longer actually sure there's a hang, just something slow.=20=20
>> That's even more of a grey area, but I think it's sane to call a 1-hour=
=20
>> link time a regression -- unless it's expected that this is just very=20
>> slow to link?
>
> I dunno, if it was only a thing for allyesconfig, then whatever - but
> it's gonna significantly increase build times for any large kernels if LLD
> is this much slower than LD. Regression in my book.
>
> I'm gonna go and experiment with mixed toolchain builds, I'll report
> back..

I took palmer/for-next (1bd2963b2175 ("Merge patch series "riscv: enable
HAVE_LD_DEAD_CODE_DATA_ELIMINATION"")) for a tuxmake build with llvm-16:

  | ~/src/tuxmake/run -v --wrapper ccache --target-arch riscv \
  |     --toolchain=3Dllvm-16 --runtime docker --directory . -k \
  |     allyesconfig

Took forever, but passed after 2.5h.

CONFIG_CC_VERSION_TEXT=3D"Debian clang version 16.0.6 (++20230610113307+7cb=
f1a259152-1~exp1~20230610233402.106)"


Bj=C3=B6rn