Very slow vector chart performance with Raspberry Pi?

[sv_blackbird]

I've built a Raspberry Pi to (hopefully) replace my old Windows laptop. There were no technical issues in getting it running with OpenCPN 5.2.4. It's a 8Gb 4B and a 64Gb Sandisk "Extreme" SD card. I'm currently plugged in to my desktop monitor running at 1920 x 1080; I'll probably use a 14" "portable" monitor running at the same resolution on the boat.


I've loaded the US RNCs and ENCs (and a few other free RNCs).



So far, the graphics performance with vector charts is VERY slow. As an example, a single click on the "+" icon to zoom in takes 3 - 4 seconds. This is linear; if I click twice it's 7 - 8 seconds. Dragging a chart is equally painful, with the added caveat that the wait cursor isn't visible while the screen repaints, so it's hard to tell if the action is complete.


I'm convinced that there must be something in my setup that's the problem, but so far I haven't found it. I did try tweaking gpu_mem in /boot/config.txt with no noticeable change.


Any suggestions on how to improve this performance?


Thanks!


Dan

[Hakan]

Dan..
First:
Options->View->Advanced-> Chart Zoom/Scale weighting: Check that the two sliders for Raster and Vector are both set to "0" for a start.

Second:
To many chart files for the same area can "cost".
Third:
Viewing a chart file for the very first time can consume some time to build the cache. Subsequent openings will be fast.

[verkerkbr]

Only use the charts set you need for a certain area. Activate OpenGL (not the software version).

I'am using a 64 bits OS version. Works faster.

With the system software on a small 128 GB SSD HD drive via usb3. Then you dont't need an SD card. You can easily copy the SD image to an SSD image.


Bram

[bcn]

When using RNCs the first time those will be processed to optimize. Depending on the system you will see a considerable load and delay.

Same happens to ENCs while converting them to the OCPN SENC format.

[sv_blackbird]

My understanding was the 64-bit on Raspberry Pi wasn't supported . . . . I can try the SSD; I have an old 256Gb drive here that I removed from a laptop, so that's an easy experiment.


I did have all the charts downloads in a single giant tree / chart catalog; I'm going back and re-organizing based on the Coast Guard districts - once that's done I can set up "rational" chart groups . . . . .

Thanks for the suggestions - I'll keep playing with it :-)


Dan

[AedanC]

Are you zoomed out a lot? The further out you are zoomed the more data the Pi has to handle and the slower it gets. Start with something about 10nm across and see how you get on.

[verkerkbr]

Originally Posted by sv_blackbird

My understanding was the 64-bit on Raspberry Pi wasn't supported . . . . I can try the SSD; I have an old 256Gb drive here that I removed from a laptop, so that's an easy experiment.

I did have all the charts downloads in a single giant tree / chart catalog; I'm going back and re-organizing based on the Coast Guard districts - once that's done I can set up "rational" chart groups . . . . .

Thanks for the suggestions - I'll keep playing with it :-)


Dan

Although there is still no official 64 bit version of the RaspiOS. But it is availble for a long time also with the kernel V8 support for 64 bits.

Then there is also a 64 bits Ubuntu version for the RPI. Called Groovy Gorilla.
Works very good and you can install also most of the OpenPlotter add-ons.

For the SSD you need a connection for usb3.1. And you must have the latest Eeprom version which boots from an SSD. Use the RaspiOS to install the eeprom version. Most of the time it comes together with other updates. There has been a lot of improvements. Update is: sudo apt update and then sudo apt upgrade in the terminal.

First make a working SD image. And then copy the image to the SSD. The copy software is available in the RaspiOS 64 bits.

Bram

[sv_blackbird]

Thanks to everyone for the suggestions!!!

• I AM working with a small area - I've been testing with a 15-mile long section of Long Island Sound ("home" :-)
• Normally I check the "Prepare all ENC Charts" checkbox before I try to actually view anything, so in theory, any given chart should not NEED to be "prepared" when I zoom or pan to it.
• I do have OpenGL enabled - not sure how much difference this will make on the Raspberry Pi 4

I'll definitely try a 64-bit image too; there are plenty of spare SD cards around :-)


Dan

[fgd3]

Originally Posted by bcn

When using RNCs the first time those will be processed to optimize.

Did you perhaps mean to write ENCs? My understanding is that RNCs are just images which don't require processing.

[bcn]

Originally Posted by fgd3

Did you perhaps mean to write ENCs? My understanding is that RNCs are just images which don't require processing.

RNCs are getting optimized as well (if OpenGL enabled). If you watch carefully when a raster chart is visited the first time, you will see how the aspect changes very slightly. Due to the compression applied.

[sv_blackbird]

[SOLVED]


Final resolution is a combination of the various suggested items:

1. Change the chart directories from ONE top-level choice to many. For the US ENC's, I did this based on the CG districts.
2. Set up chart groups. I ended up with "US East Coast", "US West Coast", etc, a total of about 10 groups for the charts I have. This had the single largest effect!
3. Turn on OpenGL. Also a large effect.
4. Move Raspbian from an SD card to an SSD. It is plugged in to one of the USB 3.1 ports on the Pi. This actually made a relatively small difference.

Thanks to everyone for the help!

Note that switching to the 64-bit beta build for the OS didn't seem to make a noticeable difference is the video performance, but I didn't compare other items like "Prepare ENCs" which might show more benefit.


Dan