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Reprinted from 44606770 at 00:17 on April 12, 2010 Reading (loading. ..) Comments (0) Category: Technical documentation 1. frequency
also called clock frequency, in units of MHz, is used to indicate CPU operation speed. The frequency = CPU FSB × multiplication factor. Many people think that CPU frequency to determine the running speed, this is not just a one-sided, and the server is concerned, this understanding has gone wrong. So far, there is no formula to achieve a certain frequency and the actual speed of operation of the numerical relationship between the two, even two processor manufacturers Intel and AMD, at this point there are a lot of controversies, from the Intel the development trend of products, you can see Intel is focused on strengthening the development of its own frequency. Like other processor manufacturers, some people have won the Transmeta 1G to do a quick comparison, and its efficiency is equivalent to 2G of Intel processors.
Therefore, CPU's frequency and the actual computing power of CPU is not directly related, in CPU frequency, said digital pulse signal within the shock speed. In Intel's processors, we can also see examples of this: 1 GHz Itanium chip will behave almost as 2.66 GHz Xeon / Opteron as fast, or about 1.5 GHz Itanium 2 with 4 GHz Xeon / Opteron as fast. CPU CPU operation speed depends on various aspects of the pipeline's performance.
course, the frequency and the actual speed of operation is concerned, can only say that frequency is only one aspect of CPU performance, and do not represent the overall CPU performance.
2. FSB
FSB is the CPU benchmark rate, the unit is MHz. CPU FSB motherboard determines the speed block. Plainly, in the desktop machine, we are talking about overclocking, CPU FSB is over (of course under normal circumstances,
la gear sneakers, CPU's multiplier is locked) I believe this is well understood. But in terms of server CPU, overclocking is absolutely not allowed. Speaking in front of the motherboard CPU determines the speed, the two are running in parallel, if the server CPU overclocking, and changing the FSB, will generate an asynchronous operation, (a lot of desktop motherboards support asynchronous operation) that would cause the entire server system instability.
most current computer system memory and the motherboard FSB is running between the synchronous speed, in this way can be understood as memory, CPU FSB directly connected to pass, to achieve synchronous operation between the two state. FSB and the front-side bus (FSB) frequency can easily be confused, the following front-side bus to talk about our difference between the two.
3. front side bus (FSB) frequency
front side bus (FSB) frequency (the bus frequency) is a direct impact on CPU and memory speed of direct data exchange. There is a formula to calculate that the data bandwidth = (bus frequency × data bandwidth) / 8, the maximum bandwidth of data transfer depends on the simultaneous transmission of data of all the width and transmission frequency. For example, now supports 64-bit Xeon Nocona, front-side bus is 800MHz, in accordance with the formula, it is the maximum bandwidth of data transmission 6.4GB / sec.
FSB and the front-side bus (FSB) frequency difference: front-side bus speed refers to the speed of data transfer, CPU and motherboard FSB is running between the synchronous speed. In other words, 100MHz FSB especially digital pulse signal in shock ten million times per second; and 100MHz front side bus CPU per second refers to the amount of acceptable data is 100MHz × 64bit ÷ 8Byte/bit = 800MB / s .
fact, Prior to IA-32 architecture we know must have three important components: Memory Controller Hub (MCH), I / O Controller Hub and PCI Hub, as is typical Intel chipset Intel 7501, Intel7505 chipset for dual Xeon processor tailored, they contain MCH provides for the CPU front side bus frequency is 533MHz, with DDR memory, front side bus bandwidth of up to 4.3GB / sec. However, with increasing processor performance to the system architecture also brings many problems. The directly to the chipset and memory to exchange data. In this case, front-side bus (FSB) frequency in the AMD Opteron processor, we talk about the do not know.
4, CPU's bit and word
bit: in digital circuits and computer techniques used in binary code only
word: computer technology in the unit of CPU time (same time) to process a number of binary digits called the word length. They are able to handle 8-bit data word length is usually called 8-bit CPU CPU. Similarly, 32-bit CPU can handle per unit time in the 32-bit word length binary data. The difference between byte and word length: the commonly used English characters with 8 bits can represent, and are usually referred to as a byte will be 8. Word length is not fixed,
la gear originals, for different CPU, not the same word length. 8-bit CPU can only handle one byte, and a 32-bit CPU can handle 4 bytes, the same way for 64-bit word length of a CPU can process 8 bytes.
5. multiplication factor
multiplication factor is the CPU FSB frequency and the relative proportions. At the same FSB, the multiplier the higher the frequency the higher the CPU. But in fact, the premise of the same FSB, the high frequency of the CPU itself significance. This is because the data transfer between CPU and system speed is limited,
la gear womens shoes, the blind pursuit of high-frequency and high frequency of the CPU will be significant speed. In addition to projects like the general version of the Intel CPU is multiplier locked, and AMD did not lock before.
6. cached
cache size is an important indicator of the CPU, and cache size on the structure and the impact of very large CPU speed, CPU cache of the operating frequency within the high and the processor is generally the same frequency operation,
la gear, efficiency is far greater than system memory and hard drive. Actual hours of work,
la gear walking shoes, CPU is often need to repeat the same data blocks read, and cache size increases, the CPU can greatly improve the hit rate of the internal read data, without memory or hard disk and then to find, in order to improve system performance . However, due to CPU chip area and cost factors to consider, the cache is very small.
L1 Cache (cache) is the CPU cache, the first layer is divided into data cache and instruction cache. Built-in L1 cache size and structure of the greater impact on the performance of CPU, but by the static RAM cache composition, structure more complex, the CPU die area can not be the case too, L1 cache capacity level can not do too much. General server CPU's L1 cache size typically 32-256KB.
L2 Cache (secondary cache) is the CPU's second level cache, both internal and external sub-chip. Internal chip secondary cache same speed and frequency, while the external secondary cache is only half the frequency. L2 cache size will also affect the CPU's performance, the principle is the bigger the better, and now the family is the biggest with the CPU capacity of 512KB, and the server and workstation CPU's L2 cache with as much as 256-1MB, 2MB or 3MB, some as high as .
L3 Cache (three-level cache), divided into two types, early is external, and now are built. The practical effect of it is, L3 cache memory, applications can further reduce latency and increase the large amount of data processor performance calculation. Lower memory latency and improve computing power for large data games are helpful. The L3 cache in the server space to increase performance is still significantly improved. For example, the configuration with a larger L3 cache will be more effective use of physical memory, so it is relatively slow disk I / O subsystem can handle more data requests. Processor with a larger L3 cache file system to provide more efficient caching behavior and the short message and processor queue length.
In fact, the first L3 cache
be used in AMD's K6-III processor, when the L3 cache is limited by manufacturing processes, and have not been integrated into the chip, but integrated on the motherboard. In the only system bus frequency can be synchronized and L3 cache with main memory in fact little different. Later, using the L3 cache,
la gear shoes, Intel introduced the Itanium server processor market. Next is the P4EE and Xeon MP. Intel also plans to launch a 9MB L3 cache Itanium2 processor, 24MB L3 cache and future dual-core Itanium2 processors.
but basically L3 cache on the processor performance improvement seems not very important, for example, is equipped with 1MB L3 cache Xeon MP processor is still not the Opteron's opponent, we can see that the increase in front side bus, cache than the increase in more effective performance.
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