If you want to get a thorough understanding of a new hardware, we often need to carefully observe from various angles. In most situations, vendors will provide detailed hardware specifications and related documentation to the media, and even can be the first and the next complete analysis of hardware components; and in the software is mainly through the conversation, which is why Intel often held similar to the IDF (Intel Developer Forum) and other reasons, are to help explain how to use these hardware. Very interesting is often at the summit of the software through the exchange of our ability to obtain the real operation of the device application.
Recently, foreign media AnandTech reporter participated in the United States this week in Dezhou, Austen held a super computer exhibition (SuperComputing15), in the meeting for the second generation Phi Xeon processor, Knights (Landing KNL) on the Multi-Channel (MCDRAM), referred to as multi channel dynamic random access memory (DRAM) related information,. In this talk, the main analysis of a large number of models and tools, in addition to how the depth of the deployment of work.
An overview of some of the KNL has been exposed, such as the clock frequency limit for the 72 core Silvermont 1.3GHz based on two core is divided into a plurality of area (tile), each core equipped with two vector execution unit (VPU, AVX-512), and each area share 1MB two level cache, according to the design of the total capacity of two 36MB. Compared with the previous application in the standard model of Intel ring topology, the new processor uses a mesh topology. Although the above picture shows the 6*7, but due to some of the problems in the package, the layout may be adjusted to 4*9.
Shift Paradigm is ubiquitous in large scale. KNL can be used as the main processor of the computer, the operating system or the Phi Xeon processor as the co processor, but it is worth noting that the above for 2P/4P QPI version of the information. KNL a total of 36 PCI 3 channels, in addition to the network also provides Omni-Path control board. These cores use the Silvermont version of the 14nm, compared to the P54C 22nm claims to be able to bring substantial performance improvement. There are 10 main memory in the mold of the mold - one of which is DDR4 master (each of which supports three channels), while the other eight are MCDRAM.
KNL there are three types of memory, you need to read BIOS information in the POST time period to confirm, so consumers if you want to switch mode, then need to restart.
First of all, the first mode is the Mode Cache, which is not required for any change in code. The system will organize and arrange the data to be used as a MCDRAM for the three level cache, while DDR4 will be used as another level of memory.
The second model is called Flat (Mode), which allows the MCDRAM to have physical accessibility, allowing programmers to migrate data structures and import MCDRAM. While the third modes are mixed mode (Mode Hybrid), the integration of these two ways.