Re: Linux 6.5 speed regression, boot VERY slow with anything systemd related

[Marc Haber <mh+linux-kernel@zugschlus.de>]

On Wed, Sep 06, 2023 at 06:21:07PM +0300, Tony Lindgren wrote:
> * Marc Haber <mh+linux-kernel@zugschlus.de> [230906 14:41]:
> > If I cannot see the host boot, I cannot debug, and if I cannot type into
> > grub, I cannot find out whether removing the serial console from the
> > kernel command line fixes the issue. I have removed the network
> > interface to simplify things, so I need a working console.
> 
> I use something like this for a serial console:
> 
> -serial stdio -append "console=ttyS0 other kernel command line options"

Looks like my problem was that I had "-S" on my qemu command line with
didn't even start the VM after setting it up. Removing the -S makes VNC
and the serial console work.

The most basic reproducer I found is:

/usr/bin/qemu-system-x86_64 \
-m 768 \
-machine pc-i440fx-2.1,accel=kvm,usb=off,dump-guest-core=off \
-nodefaults \
-drive file=/dev/prom/lasso2,format=raw,if=none,id=drive-virtio-disk0,cache=none,discard=unmap,aio=native \
-device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x3,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1,write-cache=on \
-serial stdio

Simplifying the drive and device virtio-blk-pci lines prevents the
initramfs of the VM from finding the disk and thus the system doesn't
get as far to show the issue.

If you want to see it work, add
-device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1,bus=pci.0,addr=0x2 \
-vnc :1
point a vncviewer to port 5901, remove the "serial=ttyS0" configuration
and see the system run normally.

What else can I do?

Greetings
Marc

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