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Reply-To: sedat.dilek@gmail.com
From:   Sedat Dilek <sedat.dilek@gmail.com>
Date:   Sat, 13 Mar 2021 13:58:56 +0100
Message-ID: <CA+icZUWXuknBMdxTQXjJH2JiOgZbWcbk1U=dk6Zp2FgygU5Nyg@mail.gmail.com>
Subject: Re: [PATCH 0/2] x86: Remove ideal_nops[]
To:     Borislav Petkov <bp@alien8.de>
Cc:     Peter Zijlstra <peterz@infradead.org>, x86@kernel.org,
        rostedt@goodmis.org, hpa@zytor.com, torvalds@linuxfoundation.org,
        linux-kernel@vger.kernel.org, linux-toolchains@vger.kernel.org,
        jpoimboe@redhat.com, alexei.starovoitov@gmail.com,
        mhiramat@kernel.org
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On Sat, Mar 13, 2021 at 1:49 PM Borislav Petkov <bp@alien8.de> wrote:
>
> On Sat, Mar 13, 2021 at 01:38:22PM +0100, Sedat Dilek wrote:
> > AFAICS you did a 5 times x86-64 defconfig with dropped pagecache and `make -j9`?
>
> The tailored .config for that particular test box.
>
> > Does your distribution offer LLVM/Clang v12.0.0-rc3 (released this
> > week) binaries?
>
> The partition on that box I used is debian testing, so no:
>
> $ apt search llvm-1* 2>/dev/null | grep llvm-1
> libllvm-11-ocaml-dev/testing,testing 1:11.0.1-2 amd64
> llvm-10/now 1:10.0.1-8+b1 amd64 [installed,local]
> llvm-10-dev/now 1:10.0.1-8+b1 amd64 [installed,local]
> llvm-10-runtime/now 1:10.0.1-8+b1 amd64 [installed,local]
> llvm-10-tools/now 1:10.0.1-8+b1 amd64 [installed,local]
> llvm-11/testing,testing,now 1:11.0.1-2 amd64 [installed,automatic]
> llvm-11-dev/testing,testing,now 1:11.0.1-2 amd64 [installed,automatic]
> llvm-11-doc/testing,testing 1:11.0.1-2 all
> llvm-11-examples/testing,testing 1:11.0.1-2 all
> llvm-11-runtime/testing,testing,now 1:11.0.1-2 amd64 [installed,automatic]
> llvm-11-tools/testing,testing,now 1:11.0.1-2 amd64 [installed,automatic]
>

You can add Debian/experimental APT sources.list ...

[ /etc/apt/sources.list.d/debian-experimental.list  ]
deb http://ftp.debian.org/debian experimental main contrib non-free
deb https://deb.debian.org/debian experimental main non-free contrib

[ /etc/apt/preferences.d/99_debian-experimental.pref ]
Package: *
Pin: release o=Debian,a=experimental
Pin-Priority: 99

This gives LLVM/Clang v12 packages an APT prio of 99 - meaning no
auto-upgrade installations will be done.
You have full control by doing it manually.

Renew informations from APT repositories:

root# apt-get update

What clang-12 version is/are available?

root# apt-cache policy clang-12

Simulate an install (note: --no-install-recommends option):

root# apt-get install llvm-12 clang-12 lld-12 llvm-12-tools
--no-install-recommends -t experimental -s

option -s: simulate

Really do an installation of LLVM/Clang v12 stuff:

root# apt-get install llvm-12 clang-12 lld-12 llvm-12-tools
--no-install-recommends -t experimental -y

option -y: yes

If you like to test.

Of course you can use packages from <apt-llvm.org> repositories.
I can give you APT sources.list plus pref files if you desire.

Have more fun.

- Sedat -