[Mesa-dev] Fw: [Intel-gfx] Very low performance when streaming textures

[Ben Widawsky]

mesa-dev is a better place for this question.

Begin forwarded message:

Date: Mon, 21 Jan 2013 22:13:34 +0100
From: Marcel Witte <wittemar at gmail.com>
To: intel-gfx at lists.freedesktop.org
Subject: [Intel-gfx] Very low performance when streaming textures


Hi,

I'm refering to the example of this article about streaming textures
and using Pixel Buffer Objects: http://www.songho.ca/opengl/gl_pbo.html

The PBO Unpack example
(http://www.songho.ca/opengl/files/pboUnpack.zip) is creating an
"animated texture" and can switch between three modes: Direct
transfering of the texture using glTexSubImage2D, and using one or two
PBOs for better performance.

I'm running this example on an notebook with an Intel Core i7-2630QM
and an Nvidia Geforce GT 550M with Optimus. If I'm using the Nvidia
card using optirun I get the expected high performance, using direct
tranfer about 150 fps and using PBOs about 400 fps. But if I'm using
the intel card I get really slow rates, about 40 fps in direct mode and
even worse about 10 fps using PBOs.

Running the same example with windows I get about 100 fps using the
intel card in every mode.

Is this expected behaviour or is this a bug in the intel linux driver?
How can I improve the performance? I hope you can help me here as I'm
writing a real application using a video as texture.

Regards,
Marcel Witte
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