SDL2 slow on mac pro?

The rectangle should move across the window in one seconds, instead it’s taking multi seconds.
setting it to SDL_RENDERER_SOFTWARE is much faster.
here is the complete code, https://gist.github.com/spaceexperiment/d2b465ab071e821c84c925b7f20f3279 .
I asked this question on reddit too, and a guy compiled it on windows and said it was working as expected. so i guess it’s a mac issue.
here is the question on reddit https://www.reddit.com/r/sdl/comments/54awxu/slow_on_hardware_acceleration/.

running valgrind ./rect yields this https://gist.github.com/spaceexperiment/5bbe6eb7c9a7b2d7e65786dbc12e13c4

Perhaps VSync is getting enabled? That can limit the app’s framerate.

– David L.