What is special about Piton, an advanced chip designed for data centers?

At the Hot Chips Conference in San Francisco on August 23rd, Princeton University researchers published details of their 25-core processor chip called Piton and proposed to fill a computer with 8,000 Pitons and create 200,000. The extraordinary idea of ​​the total number of computers in the kernel.

The general personal computer's chip has only 4-8 cores, and Piton is tailor-made for large data centers to support large-volume data, highly scalable, and capable of supporting multiple processor cores. If the idea of ​​a 200,000-core computer is really realized, it depends on which company is willing to use it.

Piton can greatly improve the computational data and save energy, and its construction has excellent scalability, which means that thousands of such chips can be combined to form an overall system with millions of processors.

David Wentzlaff, a professor at Princeton University, said: “In the Piton production project, we rethought the architecture of the computer and created such a special chip for the data center and the cloud. This is one of the largest chips currently produced by the academic community. Can run more efficiently and is cheaper."

Piton is the result of years of joint efforts by Wentzlaff and his students. The current version is 6mm x 6mm in area, contains 460 million transistors, each transistor is only 32 nanometers long, in addition to the electron microscope, these transistors can not be seen by the naked eye at all. .

In general, Piton has the following three characteristics:

"Executing breaking wind"

Piton's design focuses on mining commonalities of running programs on the same chip. One of these methods is called "Execution Drafting". This is very similar to the fact that in the bicycle race, the drivers form a specific formation and use the drafting formed by the cyclists breaking the wind. Reducing resistance saves energy.

In a data center, programs that are usually run by multiple users rely on similar processor operations. Piton's kernels can recognize the relationship between these programs and execute the same instructions in succession, so the kernel runs one after the other, just like a racing driver. The researchers said that the effect of this operation is that it can increase energy efficiency by about 20% compared to the normal core.

Traffic Shaper

In general, multiple programs mutually occupy computer memory. Piton will have a memory-traffic shaper. This function is like a "traffic policeman" at a busy intersection. It evaluates the needs of each program, adjusts their memory requests accordingly, and directs the program. We circulate smoothly and avoid clogging. Compared with the traditional distribution method, this can increase the performance of the chip by 18%.

Efficient cache management

The memory management of the Piton chip itself is also very efficient. This type of memory is what is commonly referred to as "cache." In most designs, all cores of a chip share the cache, but this strategy causes conflicts when multiple cores need to obtain and modify the cache. Piton does not take this shared approach, but allocates different uses for cached regions and specific kernels. The researchers said that as a result, the efficiency of each chip can be increased by 29%, and when the millions of cores in a data center run together, the efficiency of the system will multiply.

The researchers said that these improved characteristics, consistent with existing production standards, can be applied to production practices. In order to promote the development and application of Piton, Princeton University has already open-sourced Piton's design. The public and researchers can click this website to obtain relevant information.

Via Princeton University News Room