Medley rendering performance with and without VNC

[pamoroso]

The videos in this .zip file demonstrate the graphics rendering performance of Medley with and without VNC: medley-vnc-linux.zip

The screencasts show the opening of a file browser that lists the files in my logindir. I recorded the videos on Linux Mint 22 Cinnamon with Medley built for X:

• medley-vnc.webm: with TigerVNC
• medley-novnc.webm: without TigerVNC

[nbriggs]

I think what you're seeing is not a difference in medley's rendering performance (it can't do anything but make exactly the same X calls in both cases) - its your graphics pipeline, and the immediate visibility of renders to the X/Wayland display in the no-vnc case vs the buffering that's going on in the VNC case, along with any other underlying X server variations like whether it has (and uses) shared memory for the image transfers (see the xdpyinfo extension list for both the native and VNC display cases)

I'd suggest looking at the "click to clunk" time (as we characterized it in the printer business) -- use the exact same test each time, and get the human interaction out of it by doing something like

(FILEBROWSER "{dsk}<path>to>medley>library>*.TEDIT" NIL '(:REGION (100 100 700 800)))

record the video, and note the elapsed time from the point you hit return on the command to the point the display is complete.

[pamoroso]

I'll do, this was just a quick demo to showcase the performance difference.

[pamoroso]

I recorded new videos of Medley evaluating the test expression (FILEBROWSER "{MEDLEY}library>*.TEDIT" NIL '(:REGION (100 100 700 800))) with and without VNC: medley-vnc2.zip

I pasted the expression without the last closing parenthesis in the Exec and then typed the parenthesis. Next, I used a video editor to measure the time elapsed between the typed parenthesis and the end of the rendering activity in the File Browser. These are the results:

• no VNC: 2.6s
• VNC: 0.3s

So the time without VNC is apparently one order of magnitude larger than with VNC.

[pamoroso]

Just a reminder that I ran the experiment on a 5 GHz 13th gen Intel Core i7 PC with 32 GB RAM under Linux Mint 22 Cinnamon with X11.