Possible bug: PBO + glCompressedTexSubImage3D + Texture Array Performance Issue

Hello there,

i’ve a problem with updating a texture array with compressed data per glCompressedTexSubImage3D.

I have an PBO which stores the compressed data, which i want to use to update a 2D array texture.
Unfortunately the updating process is very slow and needs 100 ms and more to finish.
The upload process to the GPU is already finished when i call glCompressedTexSubImage3D, because i use
fences to check for that.

What’s odd is the fact, that this problem does only occur if i create an array texture with more then one layer.
With one layer it works like a charm. If i create an array texture with let’s say 2 layers, the problem even occurs for the first layer.
My driver version is 331.38 and i use linux.

I’m also using a debug context which doesn’t display any error messages.

I found a thread at the OpenGl forum where someone also complains about performance issues.

https://www.opengl.org/discussion_boards/showthread.php/182639-Possible-NVidia-Driver-Bug-319-49

This maybe the same issue i’m encountering. He also provides a sample program.