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Date:   Mon, 11 Sep 2023 15:53:40 +0300
From:   Tony Lindgren <tony@atomide.com>
To:     Marc Haber <mh+linux-kernel@zugschlus.de>
Cc:     Sean Christopherson <seanjc@google.com>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        linux-kernel@vger.kernel.org,
        Linux Regressions <regressions@lists.linux.dev>,
        Linux KVM <kvm@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: Linux 6.5 speed regression, boot VERY slow with anything systemd
 related
Message-ID: <20230911125340.GB5285@atomide.com>
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* Marc Haber <mh+linux-kernel@zugschlus.de> [230909 20:08]:
> On Thu, Sep 07, 2023 at 01:51:50PM +0300, Tony Lindgren wrote:
> > Still a minimal reproducable test case is needed.. Or do you have the
> > dmesg output of the failing boot?
> 
> I have both dmesg output of a failing boot (with my kernel) and of a
> successful boot (with the Debian kernel). Attached.

Thanks I don't see anything strange there, serial ports are probed in
both cases.

> In the last few days I have made some additional experiments. Since 6.5
> has landed in Debian experimental in the mean time, I tried with the
> Debian kernel: It works. I then used the Debian .config with my kernel
> tree and my build environment, it works as well. I tried again with my
> own .config, doesn't work.

OK

> I spent the next days with kind of binary searching the .config
> differences between mine and Debian's (they're huge), and I now have two
> configurations that only differ in CONFIG_PREEMPT_VOLUNTARY and
> CONFIG_PREMPT. The version with CONFIG_PREEMPT_VOLUNTARY seems to work
> (both attached). Sadly, my "own" .config uses CONFIG_PREEMPT_VOLUNTARY
> and doesn't work, so the actual problem seems to be a bit more complex
> still.

OK

Regards,

Tony