Skip to content

LVGL Benchmark — C

Source: apps/c/heap/lvgl_benchmark/src/app.c (and apps/c/zeroheap/lvgl_benchmark/).

The C port calls the LVGL C API directly through <ove/lvgl.h> — ove_lvgl_lock() / ove_lvgl_unlock() are the only oveRTOS-specific calls; everything else is upstream LVGL.

Build

make host.posix.lvgl_benchmark      # POSIX host + browser dashboard
make qemu.freertos.lvgl_benchmark   # QEMU + FreeRTOS
make                                 # build
make run                             # run

Scene registration

Each scene is a function that builds a tree of LVGL widgets on lv_screen_active():

static void rectangle_create(void)
{
    lv_obj_t *obj = lv_obj_create(lv_screen_active());
    lv_obj_set_size(obj, 200, 200);
    lv_obj_center(obj);
    lv_obj_set_style_bg_color(obj, lv_color_hex(0xff0000), 0);
}

A static table pairs the scene name with its builder:

static scene_dsc_t scenes[] = {
    { "Empty screen",            empty_create,             0, 0, 0, 0, 0, 0 },
    { "Rectangle",               rectangle_create,         0, 0, 0, 0, 0, 0 },
    { "Rectangle, rounded",      rectangle_rounded_create, 0, 0, 0, 0, 0, 0 },
    /* … */
};

Scene rotation

A periodic LVGL timer fires every scene_time ms to record metrics and load the next scene:

static void next_scene_timer_cb(lv_timer_t *timer)
{
    /* Record current scene's metrics from LVGL's perf monitor. */
    scenes[current_scene].fps_avg = ...;

    current_scene++;
    if (current_scene >= ARRAY_SIZE(scenes)) {
        summary_create();
        lv_timer_del(timer);
        return;
    }

    lv_obj_clean(lv_screen_active());
    scenes[current_scene].create_cb();
}

lv_timer_* is LVGL's own timer engine, not ove_timer_* — LVGL timers run from lv_timer_handler() on the graphics thread, so they're already synchronised with the rest of LVGL.

Locking

The benchmark builds and tears down widgets from the graphics thread, so it doesn't need explicit ove_lvgl_lock() calls. If your own benchmark variation builds widgets from another thread (a network response, a sensor sample), wrap the construction:

ove_lvgl_lock();
lv_obj_t *card = lv_obj_create(parent);
ove_lvgl_unlock();

Assets

Image scenes use LVGL's compile-time image format. The C array is generated at build time from PNGs and listed in app.yaml:

sources:
  - src/app.c
  - src/benchmark_perf.c
  - src/assets/benchmark_cogwheel_rgb.c
  - src/assets/benchmark_cogwheel_argb.c
  - src/assets/benchmark_avatar.c

The PNG-to-C conversion happens via scripts/lvgl_img_conv.py invoked by the build system.

Where to next

  • The summary table at the end of the run pastes cleanly into make benchmarks reports.
  • Compare numbers across bindings: C++, Rust, Zig.
  • LVGL API: https://docs.lvgl.io/master/
  • oveRTOS LVGL integration internals: bindings/cpp/ove/lvgl.hpp (the highest-level wrapper still pairs to the raw C API used here).