Finally, Microsoft has revealed precisely what is inside its Holographic Processing Unit (HPU) chip used in its virtual reality HoloLens specs. Microsoft has been withholding the details of its special Holographic Processing Unit (HPU). Microsoft had revealed most of the HoloLens specifications earlier in the year. This special HPU is designed to perform most of the processing so that the GPU and CPU will be able to just launch applications as well as display the holograms. Microsoft custom designed the HPU which takes all of the required data from the sensors and cameras and processes it in real-time enabling you with the opportunity to make use of gestures, accurately.
At the Hot Chips conference in Cupertino, California this week, Microsoft devices engineer Nick Baker gave an exhibition on precisely what’s inside the HPU and how powerful it is. Microsoft’s special custom-designed HPU is a TSMC-fabricated 28nm coprocessor which also has 24 Tensilica DSP cores. It comes with 8MB of SRAM, about 65 million logic gates, and a supplementary layer of 1GB of low-power DDR3 RAM on top. All these in a 12mm-by-12mm BGA package. That RAM is distinct to the 1GB which is available for the Intel Atom Cherry Trail processor. The HPU will be able to handle up to a trillion calculations per second.
It takes care of all the environment sensing and other input and output conditions required for the virtual reality spectacles. It collates data from sensors and processes the gesture movements of the wearer, all in hardware. This makes it faster than the equivalent code running on a general purpose CPU. Each DSP core is assigned a particular task to focus on.
The Microsoft HPU is low-powered. It draws less than 10W from the power supply in order to handle gesture and environment sensing. It also comprises of PCIe and standard serial interfaces. Microsoft has succeeded in adding 10 custom instructions in order to speed up special instructions made by HoloLens for its augmented reality algorithms. Overall, the unit is capable of accelerating algorithms up to 200 times faster compared to when in pure software.
The unit sits together with a 14nm Intel Atom x86 Cherry Trail system-on-chip, which has its own 1GB of RAM and runs Windows 10 and applications that take advantage of the immersive noggin-fitted display. Data shuttled over to the host Atom processor is as cooked as possible. This means that the x86 CPU will not have to perform lots of extra processing work on the information taken from the HPU.
The slides and information were revealed by Microsoft Devices Group engineer Nick Baker, who said Redmond overruled making use of traditional CPUs or CPU-GPU SoCs in favor of a personalized design that includes programmable elements and hardware acceleration. None of the DSP cores are each pushed further than 50 per cent capacity at the moment, thus future-proofing the product. Finally, the HPU’s design makes it possible for Microsoft’s engineers to guarantee duty cycles and latency during processing.
The details were revealed at the Hot Chips conference in Cupertino, California. Next year Windows 10 PCs can use it to provide a 3D desktop environment.