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AMD publishes Linux HSA kernel driver.

PostPosted: Wed Jul 16, 2014 12:44 am
by pam
http://www.phoronix.com/scan.php?page=n ... px=MTczOTY

AMD has published the HSA(Heterogenous Systems Architecture) kernel driver code for the Linux Kernel.
It has around 10000 lines of code.

HSA is a technology that has been AMD's goal since it bought ATI technologies back in 2006. It has finally materialized.

What is HSA?
HSA is a technology that is implemented by AMD for their APU's(Accelerated Processing Unit).
Most people might be aware that an APU, also called as an Accelerator has a GPU and CPU on a single chip of Silicon. That is an incorrect concept.

An APU chip at the hardware level handles data very differently compared to a CPU with an external connected GPU. Data(software) is unaware whether it is being processed by the CPU or GPU in an APU and the kernel is responsible to make the APU recognize how it should handle the data. So the data processing is now shared between the CPU and GPU. Not only that they share the same memory(cache) and communicate between each other as to where and how the data should be processed.

Data passing through the CPU cannot be halted mid way and then passed on to the GPU. An HSA chip does exactly the opposite. The kernel driver for HSA is responsible for helping the APU recognize what sort of data and shared processing it can do inter and intra, inside the APU.

The CPU is a serial processor.
The GPU is a parallel processor.
A parallel processor also has scaling capabilities, i.e. data does NOT need to wait for data that has finished processing. In HSA, CPU+GPU cores == Compute cores.

Real world tasks that require immense computing resources are done on the GPU. For example the program Blender on linux uses CUDA. CUDA is a parallel processing technology that is used by NVIDIA for their GPU's. Up until now AMD did not have a working solution. HSA is an answer for GPGPU(General-purpose computing on graphics processing units).

The PS4 and Xbox-One have AMD HSA chips.

The AMD A series APU's like 7850k/7700k are HSA chips.
The AMD Kabini chips like the athlon 5150/5350 are low powered/low cost HSA chips.

Kernel 3.17 will have HSA enabled by default.

AMD Carrizo HSA chips will be released mid 2015 and will have HBM(High Bandwidth Memory) and stacked DRAM having a data throughput of 256GBps, higher than DDR4, feeding the starved compute cores. It will not only be more powerful but also cheaper to manufacture and implement compared to Level-3 SRAM cache inside the CPU.

http://electroiq.com/blog/2013/12/amd-a ... ry-stacks/