[qemu-s390x] qemu-system-s390x slowdown (regression ?) with qemu v4.0.0

[Guenter Roeck]

Hi,

I noticed that qemu-system-s390x is much slower when running qemu v4.0.0
vs. qemu v3.1.0. Specifically, on a system with Ryzen 2700X, a boot test
has a runtime of ~25 seconds with qemu v3.1.0, but ~67 seconds with qemu
v4.0.0.  Mainline qemu as of today (6/12) is even worse, with a runtime
of ~73 seconds.
All of this is booting exactly the same kernel and root file system.
All qemu versions are compiled locally with gcc 6.5.0, with the same
configuration options enabled.

Is this a known problem ?

Thanks,
Guenter