2 Screens on separate DMA and dedicated cpu cores

[MisterAG]

Hi,

I'm working on a project using a single ESP32 to drive 2 GC9A01 screens (see my previous post).
At first I was using the 2 screens on VSPI which worked fine, except I wanted to optimize the performance.

For that I put screen 0 on VSPI and screen 1 on HSPI. I wrote a function refreshMyScreen(x) that refreshes the specified screen with a refresh rate that I can specify for each screen (screenDelay=0 => refresh as fast as possible.)

This works if I call refreshMyScreen(0) and refreshMyScreen(1) within loop(), although with no performance benefit (as expected).

Since the ESP32 has a dual core cpu, I then moved the refreshMyScreen(1) to run on cpu core 0, refreshMyScreen(0) remains in loop() which runs on cpu core 1. The framerate improved but a lot of artifacts are being shown on the screen. I then suspected the DMA channel of the bus instance to be the culprit. Basically using DMA channel 1 on both screens, or using DMA channel 1 & 2, results in artifacts when running on two cores. Using DMA 1 on screen 0 and DMA 0 (=disabled) on screen 1, improves the performance of screen 0 but (as expected) not on screen 1.

Summarized:
On 2 cores
DMA FPS1 FPS2 result
1,1 463 432 *Artifacts
1,2 463 432 *Artifacts https://www.youtube.com/shorts/mffwnWgIuXs
1,0 464 232 OK, different speed https://www.youtube.com/shorts/AQ8_XQLOAlk
On one core
1,2 233 233 OK https://www.youtube.com/shorts/uawKLMwyr3U
1,1 233 233 OK
1,0 229 229 OK

I suppose it's not possible to use different DMA channels which get called at the same time by a process running on a dedicated cpu core and avoid the artifacts?
Any other way I could improve performance?
lovyandualcore-dualscreen.zip

Best regards,
Jan