Processor designers are coming up with new tricks to get the most out of their new architectures, one of which is to increase the clock speed of a single core above the common limit of the entire processor. This is called a single-core boost and in this article we will explain what it is and what benefits it brings to your PCs.
More veterans will remember the years when processors were single-core and couldn’t run more than one thread, that was when the race was for the highest amount of MHz first GHz later, until they can no longer ride for the physical. limitations and had to switch to multicore.
One feature that we are going to see in newer processors is single-core boost, which is where a single core of a multi-core processor achieves a higher clock speed than the boost for multiple cores, all thanks to to the ability to disconnect the rest of the cores from the processor, reduce their clock speed, or prevent them from reaching boost speed.
Single-core boost, CPU power redistribution
The clock speed that a processor can achieve depends on the amount of power available to it, but processors have pitfalls to better optimize power consumption, although most are based on the possibility of always disconnect unused parts of the processor so that they do not consume power during Do nothing.
At the kernel level, many designs that can work with multiple threads tend to execute certain instructions taking advantage of unit duplication of certain parts of the control unit to avoid contention and increase performance, but in the end. other designs it does not and does disable SMT or Hyperthreading in order to increase the clock speed.
By the same principles, it is possible to completely disable all but one cores and even remove SMT or Hypethreading from them so that the clock speed of a single core is as high as possible.
What does this add to the total performance of the processor?
There are many benchmarks that measure the performance of a single CPU core, these benchmarks are not used to assess absolute CPU performance, nor are they based on realistic scenarios. They simply serve us in a comparative way to know how one architecture has evolved in relation to another, by comparing heart by heart.
In the programs that exist in the market, because for years that consumers have multiple cores, most programs are designed to run in parallel most of the time, but it must be taken into account that the programs have a part which can be parallelized and another which cannot.
If we pay attention to Amdahl’s law, the execution time of each of the parallelizable parts of the code will decrease by adding more cores, but there is a part of the code that is serial and therefore cannot be executed in parallel. , this part of the programs depend on the speed of a single heart.
If we disable all but one cores, the code that works in parallel will be negatively affected, but if we maintain base speed in all cores and apply a boost or slight advantage to any of them, then the game The code that runs serially in the program will be sped up, thus increasing system performance.
Is single-core boost the same as big.LITTLE?
Although this may remind us of the big.LITTLE concept of some low power cores, it is not the same, since in this concept the idea is to use a low power core to execute certain instructions, which are simple enough to be impossible to further optimize in terms of consumption within a core, the use of a simpler core is therefore recommended to reduce power consumption.
In “big.LITTLE” the clock speed of the cores is neither increased nor decreased, but rather the kernel that runs said program or part of the program is changed, so in a processor with this type of design we have heterogeneous formation of cores, while the increase in speed centered on a single core can occur in both homogeneous and heterogeneous sets of nuclei.
However, since clock speed is directly related to voltage in power consumption, we can conclude that increasing the clock speed of a core as opposed to “bit.LITTLE” n is not a way to save CPU power consumption.
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