Re: [Qemu-devel] Re: Extremely slow graphic updates

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Lennart Sorensen wrote:

> On Tue, Jan 20, 2009 at 06:09:33PM +0100, Samuel Thibault wrote:
>> Ah, that rings me a bell. There was problem with that, something like
>> now that sdl uses SDL_BlitSurface/SDL_Flip there is an X roundtrip,
>> which is awfully slow over ssh.  Would you be able to try without ssh?
> 
> That would be tricky since it is running on another machine.  I will
> try.  I do believe someone else said that they could confirm the slow
> behaviour with 6336 running locally as well.  It may be that some X
> drivers are slow at SDL_Flip and SDL_BlitSurface.
> 
> Hmm, my X server isn't compiled to allow tcp connections (only local
> sockets), so avoiding ssh looks hard too.
> 
> Maybe Xvnc can do it.  yeah Xvnc4 as an X server did the job, and I
> vnc'd to it so qemu was running entirely locally on the machine with an
> X connection.  Works at normal speed.
> 
> So how does one fix this, since the change in 6336 makes it rather
> painful for those where SDL_Flip and company are inefficient.
> 


At risk of being silly, why don't you just use vnc to connect to qemu,
if qemu is running on a remote machine?
Obviously sdl is optimized for the local case.

Of course if it is slow even locally, then there must be something wrong
somewhere either in qemu or in sdl.