I am using this GitHub - lvgl/lv_port_pc_vscode simulator project on Linux, and I have created UI using the SLS the lvgl version I am using is v8.3
In the main. c the application code contains 3 threads one to call lv_tick_in, one for lv_timer_handler at a fixed time duration and the third thread contains my application logic to manage the GUI by moving the lvgl objects
Now my concern is that initially when I ran the project it worked as expected but the CPU usage I was getting was above 95% and the FPS varied between 5-10 FPS, in the lv_conf.h file I have disabled the building of the example and enabled the LOGS by defining #define LV_LOG_LEVEL LV_LOG_LEVEL_WARN in lv_conf.h
Additionally, while the application was running I was getting some errors as shown in below photos
Then I searched online for this error and found that I need to use a semaphore or mutex to guard all the lv_… APIs as LVGL is not fully thread safe(as mentioned here Operating system and interrupts — LVGL documentation) after doing so I was able to get 33 fps and CPU usage below 5%
So my question is my approach of using the semaphore is correct or do I have to do something else to get rid of the error, high CPU usage and low FPS
you mean that i can call lv_tick_in in os timer and call lv_timer_handler and all other lv_… apis in same thread?
I can not call the lv_timer_handler and other LVGL APIs in the same thread due to some other constrains of the application, so is it ok to call lv_timer_handler and use mutex for synchronisation?
I am getting the input from the buttons to move the objects and update them, which is event-based and some other objects are moving at different timings, for lv_timer_handler we have to call it at an interval
even if I manage to call lv_timer_handler and other APIs in a single thread then a semaphore is not required, right?
LVGL for buttons have indev system and or you can if in while where is lv_timer_hadler no problem.
Foe repeatly exist lv_timers system …
Yes no semaphore/lock then.
Try start with understand how lvgl works.
Stage 1 setup
Stage 2 guiloop
Stage 3 background.
In setup you can add many threads , but only one with guiloop and manipulate lv.
If you use arduino loop is created task designed for this , but you can use other
And background is inc_tick or other tick measure methods, another background is dma lcd driver parts etc.
Example loop symbolic code :
void loop()
{
lv_timer_handler();
delay(5);
//all next code must took micro seconds
//for slow create next threads and set event markers for show results
if(once) {
//here for example start lv_timers = periodical lv operations callbacks
}
if(event1) {
}
}
and what do lv_time_handler = do all lvgl jobs:
ask lvgl core is any callback wait do it
is tick over set indev refresh … do indev scan …
is tick over screen refresh … do if somethink changed
