I have been working with GL_MAP_PERSISTENT_BIT and glBufferStorage/glMapBufferRange. I am curious if there is an improvement in performance possible using GL_MAP_UNSYNCHRONIZED_BIT.
I already found Opengl Unsynchronized/Non-blocking Map
But the answer seems to be a bit contradictory to me. It's said there that you need to sync or block when using this flag. What is the point of setting it unsynchronized if I have to sync it later then anyway? Also I tried this combination and was not able to see any performance difference. Does it even make sense together with persistent mapped buffers? I found literally no examples about such a usage. The mentioned topic also says that you can
issue a barrier or flush that region of the buffer explicitly
But every attempt I made so far using these only resulted in garbage.
I am using currently triple buffering, but since I have to deal with very small chunks of data sometimes which I hardly can batch I had to find out that glBufferData is often faster in these cases and persistent buffers only of (huge) benefit if I can batch and reduce also the amount of drawcalls. Using GL_MAP_UNSYNCHRONIZED_BIT could be the key here.
Can anyone give me a working example, in case it even makes sense in this combination?