GPU-programmers are the expert in AoS vs SoA formats. And when you look at how RGB values are stored, its… incredibly complex. Sometimes you’ve got RRRRGGGGBBBB, sometimes its RGBARGBARGBA, sometimes its YYYYUUVV. What’s best for performance changes dramatically on system-to-system, requiring lots of benchmarking and ultimately… a massive slew of processor-specific / ARM NEON instructions that convert between every format imaginable.
On right, GPUs don’t need that processor-specific instruction because permute and bpermute instructions exist (32-way crossbar any data-to-any-lane movement, and vice versa any lane pulling from any data, permute and bpermute respectively). CPUs do need it though.
Its not so easy.
GPU-programmers are the expert in AoS vs SoA formats. And when you look at how RGB values are stored, its… incredibly complex. Sometimes you’ve got RRRRGGGGBBBB, sometimes its RGBARGBARGBA, sometimes its YYYYUUVV. What’s best for performance changes dramatically on system-to-system, requiring lots of benchmarking and ultimately… a massive slew of processor-specific / ARM NEON instructions that convert between every format imaginable.
On right, GPUs don’t need that processor-specific instruction because permute and bpermute instructions exist (32-way crossbar any data-to-any-lane movement, and vice versa any lane pulling from any data, permute and bpermute respectively). CPUs do need it though.