Re: Xfree86 is slow! with software like MATLAB

[g dot macaulay at niwa dot co dot nz]

Harold & Mark,

To contribute to the discussion:

I see the same problem when running Matlab. In my case Matlab is run on a 
Compaq/HP Tru64 computer with the GUI displayed on my Windows PC running 
cygwin/xfree in multiwindow mode. I also have a commercial X server (xwin32) 
available on my PC. Display of Matlab graphics, or even updating of the icons 
in Matlab window menubar are considerably slower when running via cygwin/xfree -
 the graphics benchmarks that Matlab provide run approximately 100 times slower 
under cygwin/xfree than under xwin32. Trials of other commercial X servers 
indicated that some are slow and some are quick, probably due to the reason 
given by Harold.

An in-house, graphically intensive, X program run under the same setup as above 
does not show such a marked difference. One point of difference is that the 
Matlab GUI is written entirely in Java, while the other program uses GTK.

Regards

Gavin

On 24 Sep 2003 at 22:27, Harold L Hunt II wrote:

> Mark,
> 
> Using the default -multiwindow mode (with the integrated window manager) 
> is slower than all of the other modes.
> 
> You can run XWin from startxwin.bat instead with:
> 
> XWin -rootless
> 
> Then you need to start a window manager like 'twm':
> 
> run twm
> 
> 
> Cygwin/XFree86 works by drawing to an offscreen framebuffer (using the 
> primary CPU), then transferring updated portions of the offscreen 
> framebuffer to the screen.  Work has begun, and is also essentially 
> stalled, on the "Native GDI" engine for Cygwin/XFree86 that translates 
> each X graphics call to a GDI graphics call; this has the advantage of 
> utilizing the power of the graphics processing unit (GPU).  Exceed and 
> possibly other commercial X Servers do something similar to the Native 
> GDI engine and are thus faster.
> 
> On a side note, the speed of your graphics card and the quality of its 
> drivers are very important for the performance of Cygwin/XFree86.  A two 
> or three year old ATI or NVIDIA PCI (AGP is better) graphics card will 
> be substantially faster than a 5 year old PCI graphics card from a 
> no-name vendor.  On the other hand, I use a 5 year old Diamond PCI 
> graphics card and it works just fine.
> 
> That's about it.
> 
> Harold
> 
> Mark Jones wrote:
> > I have tried using XFree86 (linux and cygwin) for Cygwin's XFree86 and 
> > Linux's XFree86 and have found it to be extremely slow at refreshing the
> > screen making it nearly impossible to use MATLAB's editor reasonably. 
> > However, using a MS Windows emulator like Xoftware or Hummingbird's Exceed
> > provides extremely fast response such that it is useable with various programs
> > including MATLAB.  Is there a valid reason for this?  Is it being addressed?
> > 
> > Thanks,
> > 
> > Mark
> > 
> 
>