[arch-general] qt applications over ssh tunnel: very slow redrawing

[Sergey Manucharian]

On Mon, Mar 5, 2012 at 2:20 PM, Victor Silva <vfbsilva at gmail.com> wrote:
> Maybe -C option can help:
>  -C      Requests compression of all data (including stdin, stdout,
>          stderr, and data for forwarded X11 and TCP connections).  The
>          compression algorithm is the same used by gzip(1), and the
>          “level” can be controlled by the CompressionLevel option for
>          protocol version 1.  Compression is desirable on modem lines and
>          other slow connections, but will only slow down things on fast
>          networks.  The default value can be set on a host-by-host basis
>          in the configuration files; see the Compression option.
>
Excerpts from Lukáš Jirkovský's message from Mon 05-Mar-12 20:33:
> On 5 March 2012 20:21, Jarek Sedlacek <JarekSedlacek at gmail.com> wrote:
> > That may increase the performance, but doesn't explain why GTK apps are so
> > much faster.
> >
> > Thanks,
> > Jarek Sedlacek
> >
> 
> My guess is that it's because Qt themes use lots of gradients which
> are probably transferred as a bitmap, while GTK themes doesn't use
> such fancy stuff much.

The -C option to ssh indeed improves the performance significantly. 
Also I've played with Qt themes, and even with simplest CDE or Motif 
it's very slow without compression, it is likely sending bitmaps all the time...

-- 
Cheers,
Sergey