Re: [Qemu-devel] ppc emulation and interrupts

[Blue Swirl <blauwirbel@gmail.com>]

On 1/21/09, Stefano Stabellini <stefano.stabellini@eu.citrix.com> wrote:
> Lennart Sorensen wrote:
>
>  > On Wed, Jan 21, 2009 at 11:49:10AM +0000, Stefano Stabellini wrote:
>  >> Hi all,
>  >> one of the recent problems, noticed after the displaystate change,
>  >> affects ppc emulation only and is due to the fact that none on ppc
>  >> emulation is issuing any interrupt request of the CPU_INTERRUPT_EXIT
>  >> kind if the gui timer is disabled.
>  >> Hence qemu never leaves the loop in cpu-exec.c:cpu_exec.
>  >> If the gui timer is enabled qemu is able to leave the loop because the
>  >> condition (interrupt_request & CPU_INTERRUPT_EXIT) is true when the
>  >> timer is triggered.
>  >> I think this is a problem with the ppc emulation but if you ppc guys
>  >> need the gui timer to be always on, I can arrange for it to be.
>  >> Regards,
>  >
>  > So does this explain why vnc runs fast and sdl runs slow?
>
>
>
> No, this bug prevents qemu from working when only vnc is enabled.
>
>
>
>  > Even with the latest patches, sdl is still slow for ppc emulation.  Not
>  > using much cpu either of course.
>  >
>
>
>
> I'll investigate more on this.
>  As I said before, sdl shouldn't be noticeable slower now, unless you are
>  using remote X.
>  I have just tried debian ppc and I get similar performances using vnc
>  (localhost) or sdl (local X server).

I just committed a fix, now both -nographic and VNC work for Sparc64
and VNC on PPC.