Re: [Qemu-devel] Performance regression "ioport: Switch dispatching to memory core layer"

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2013-07-15 12:52, Stefan Hajnoczi wrote:
> The following qemu.git commit adds a ~2 minute regression in boot time
> to a x86_64 live CD:
> 
>   commit b40acf99bef69fa8ab0f9092ff162fde945eec12
>   Author: Jan Kiszka <jan.kiszka@siemens.com>
>   Date:   Mon Jun 24 10:45:09 2013 +0200
> 
>       ioport: Switch dispatching to memory core layer
> 
> After the ISOLINUX menu, the display goes white and sits there for about
> 2 minutes on my laptop before the usual Linux boot screen appears.
> 
> $ qemu-system-x86_64 -enable-kvm -cpu host -m 1024 -cdrom ~/iso/livecd.iso
> 
> The parent commit immediately goes to the usual boot screen after
> ISOLINUX.  Unfortunately I don't have a ISO download link for the live
> CD.

Can you share it otherwise (before I spend time on recreating something
that does not trigger it)?

> 
> Any ideas?

What does perf say during that time? What ftrace regarding the port
numbers and access types?

Jan

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