QT4 apps slooooow in ssh

[T.C. Hollingsworth]

On Tue, May 8, 2012 at 8:47 AM, Roberto Ragusa <mail at robertoragusa.it> wrote:
> Hi,
>
> some exported (ssh -Y) applications are unbelievably slow, as they
> seem to "upload bitmaps" (display is progressively drawn from top to bottom
> and network traffic is 11.2MB/s, saturated 100Mbit/s).
>
> This happens only with qt4 apps (e.g. kate), no problem with qt3 apps or
> gtk apps.
>
> The qt4 apps run on a F16 KDE desktop with effects enabled, and are displayed
> on an F13 KDE desktop with effects disabled.
>
> The F16 machine was originally an F14 and in this case (F14 displaying on F13)
> the problem was not present.
>
> Maybe qt4 has a different rendering method which involves a lot of bitmap
> shuffling (disaster when remote)?
>
> An additional test, on the F16 machine:
> - "kate" is normally fast
> - "ssh -Y localhost kate" is slooooooooooooooooooow
>
> What is happening here????

Is `ssh -Y localhost kate -graphicssystem native` faster?

-T.C.