'Bilinear' minification filter modes (i.e., those that sample from within a single mip-level only) GL_NEAREST_MIPMAP_NEAREST and GL_LINEAR_MIPMAP_NEAREST, are 'free' and can be executed at 1 sample per clock, per fragment unit.Use of texture samplers without mipmapping tends to result in unpredictable memory access patterns, which defeat the texture cache, reduces memory efficiency, and increases memory bandwidth consumption, with a subsequent reduction in performance. Always generate mipmap chains, and enable an appropriate mipmap-selecting filter mode, for texture assets.In some cases, using these features has a performance cost, and application developers should take care to understand the impact of their use. The Tegra fragment unit incorporates sophisticated hardware texture sampling features such as bilinear, trilinear and anisotropic filter modes. No device memory is saved with these formats, and the reformatting process at specification time requires driver work on the CPU. These are expanded by the driver at specification time to 32 bit per pixel RGBX textures. Note: Tegra does not directly support 24 bit per pixel RGB textures. For example, the difference in memory footprint between an RGBA texture stored as DXT1, versus RGBA half-float, is 16x. The inflated memory bandwidth requirement (and subsequent performance impact) of the fatter texture formats can be dramatic. The following texture formats are supported by all current Tegra devices: Formatsįor each particular use case, you should choose the most compact texture format possible for the level of quality required. Use texture formats with the lowest number of bits per texel that will fulfill the needs of the source artwork and its use in the shader. Data-Related Fragment Guidelines Texturing Texture Formats Always use glClear for whole surface clears (in preference to clearing with 3D polygons). Note that glClear operates in a special optimized mode and can clear at higher than the peak 3D fragment rate. Using depth and/or stencil tests to limit fully shaded overdraw is strongly recommended for all applications with non-trivial depth complexity. Fragments can be culled at a rate of 4G fr/s (although the practical rate may be significantly lower than this, due to limited available memory bandwidth). This means that fragments can be culled by depth and stencil tests four times faster than they can be rendered. It is worth noting that early depth and stencil tests are performed before the fragment shader with a speed of 8 fragments per clock. Cardhu can shade (with the simplest possible fragment shader) at a rate of two pixels per GPU cycle, giving a final peak fragment throughput of 1G fr/s. The GPU clock in a Cardhu system operates at 520Mhz. High-Level Fragment Performance Guidelines

Android Development Tips and Tricks > Optimize OpenGL ES 2.0 Performance for Tegra > Fragment Performance Fragment Performance

Opengl 4.4 texture units