{"id":401,"date":"2020-02-11T00:16:11","date_gmt":"2020-02-10T22:16:11","guid":{"rendered":"https:\/\/scoopten.com\/?p=401"},"modified":"2020-02-27T21:44:08","modified_gmt":"2020-02-27T19:44:08","slug":"what-is-a-processor-cache-and-what-effect-it-has","status":"publish","type":"post","link":"https:\/\/scoopten.com\/what-is-a-processor-cache-and-what-effect-it-has\/","title":{"rendered":"What is processor cache and what effect it has"},"content":{"rendered":"\n
\"processor<\/figure><\/div>\n\n\n\n

CPU Cache is important. Without it, from the high processor clock speed, there would be no use. The cache allows you to use any, even the “slowest” RAM on your computer, without noticeable damage to its performance.<\/p>\n\n\n\n

Computer processors have made a significant breakthrough in development over the past few years. The size of transistors decreases every year, and productivity is growing. At the same time, Moore’s law is already becoming irrelevant. As for the performance of processors, it should be taken into account, not only the number of transistors and frequency, but also the cache volume.<\/p>\n\n\n\n

You may have already heard about the memory cache when you were looking for processor information. But, usually, we do not pay much attention to these numbers, they do not even stand out much in advertising processors. Let’s look at what the processor cache effects, what types of cache are and how it all works.<\/p>\n\n\n\n

Solving any task, the computer processor<\/a> receives from the RAM the necessary blocks of information. Having processed them, it writes the results of calculations into memory and receives the following blocks for processing. This continues until the task is completed.<\/p>\n\n\n\n

All mentioned operations are performed at a very high speed. However, even the fastest RAM is slower than any \u201cleisurely\u201d processor. Each reading of information from it and writing it back is time consuming. On average, the speed of RAM is 16 – 17 times lower than the processor speed.<\/p>\n\n\n\n\n\n\n\n

Despite such an imbalance, the processor does not stand idle and does not wait every time the RAM “issues” or “receives” data. It almost always runs at maximum speed. And all thanks to his cache.<\/p>\n\n\n\n

The processor cache is a small but very fast memory. It is built into the processor and is a kind of buffer that smooths out interruptions in the exchange of data with slower RAM. CPU Cache is often called super-random access memory.<\/p>\n\n\n\n

Processor cache is needed not only to balance the imbalance of speed. The processor processes the data in smaller portions than those in which they are stored in RAM. Therefore, the cache memory also plays the role of a kind of place for “repackaging” and temporarily storing information before transmitting it to the processor, as well as returning the processing results to RAM.<\/p>\n\n\n\n

what is processor cache<\/h2>\n\n\n\n
\"processor<\/figure>\n\n\n\n

In simple terms, the processor cache is just a very fast memory. As you already know, a computer has several types of memory. This is read-only memory that is used to store data, the operating system, and programs, such as an SSD or hard drive. The computer also uses RAM. This is random access memory, which is much faster than constant memory. Finally, the processor has even faster memory blocks, which are collectively called the cache.<\/p>\n\n\n\n

If you imagine the computer’s memory as a hierarchy by its speed, the cache will be at the top of this hierarchy. In addition, it is closest to computing cores, as it is part of the processor.<\/p>\n\n\n\n

The cache memory of the processor is a static memory (SRAM) and is designed to speed up work with RAM. Unlike dynamic random access memory (DRAM), data can be stored here without constant updating.<\/p>\n\n\n\n

How does cpu cache work?<\/h2>\n\n\n\n

As you may already know, a program is a set of instructions that a processor executes. When you start the program, the computer needs to transfer these instructions from read-only memory to the processor. And here comes the memory hierarchy. First, the data is loaded into RAM, and then transferred to the processor.<\/p>\n\n\n\n

These days, the processor can process a huge number of instructions per second. To make the most of their capabilities, the processor needs super fast memory. Therefore, a cache was developed.<\/p>\n\n\n\n

The processor’s memory controller does the job of retrieving data from RAM and sending it to the cache. Depending on the processor used in your system, this controller may be located in the northbridge of the motherboard or in the processor itself. The cache also stores the results of executing instructions in the processor. In addition, the processor cache itself also has its own hierarchy.<\/p>\n\n\n\n

Processor cache device<\/h2>\n\n\n\n

The processor cache system consists of two blocks – the cache controller and the cache itself.<\/p>\n\n\n\n

Memory cache controller<\/h3>\n\n\n\n

A memory cache controller is a device that controls the contents of the cache, retrieves the necessary information from the RAM, transfers it to the processor, and returns the calculation results to the RAM.<\/p>\n\n\n\n

When the processor core accesses the controller for some data, it checks to see if this data is in the cache. If this is the case, information from the cache is immediately given to the kernel (the so-called cache hit occurs ).<\/p>\n\n\n\n

Otherwise, the kernel has to wait for data to arrive from slow RAM. The situation when the required data is not in the cache is called a cache miss .<\/p>\n\n\n\n

The controller\u2019s task is to ensure that cache misses occur as rarely as possible, and ideally so that they do not exist at all.<\/p>\n\n\n\n

The size of the processor cache compared to the size of RAM is disproportionately small. It can only contain a copy of a tiny fraction of the data stored in RAM. But, despite this, the controller makes cache misses not often. The effectiveness of its work is determined by several factors:<\/p>\n\n\n\n