How to find out whether the last-level cache is shared between CPU and GPU?

Bo_W_2 · ‎10-20-2014

My Macbook Air has an I7-4650U processor. How can I find out whether the 4MB last-level cache is shared by the CPU and the GPU or not?

Bernard · ‎10-21-2014

I have found on Wikipedia cache article following sentence " Intel Haswell CPUs with integrated Intel Iris Pro Graphics have 128 MB of eDRAM acting essentially as an L4 cache.^[24] The benefits of an L3 cache depend on the application's access patterns."

There is no mention about the L4 cache being shared.

Bo_W_2 · ‎10-21-2014

Thanks for your comment. Although I7-4650U is a Haswell CPU, it doesn't has L4 cache. I know many ivybridge CPUs share the last-level cache with GPUs. Not sure about the Haswell notebook CPUs.

Bernard · ‎10-21-2014

Probably we should wait for the answer from Intel engineers.