超线性加速来自何处? [英] Where does super-linear speedup come from?

问题描述

在并行计算中，理论上不可能实现超线性加速.但实际上，我们确实看到了这种情况. 原因之一是缓存效果，但我无法理解它的作用.另外，还涉及其他事情，但它们又是什么呢?总之，

In parallel computing theoretically super-linear speedup is not possible. But in practice we do see such cases. One reason is cache effect but I fail to understand what does it play. Also, there are other things involved but what are they? In summary,

超线性加速怎么可能?

How are super-linear speedups possible?

我是并行计算的初学者.

I'm a beginner with respect to parallel computing.

推荐答案

假设您有一台8处理器的计算机，每个处理器具有1MB的缓存，而您的计算使用6MB的数据.

Suppose you have an 8 processor machine, each processor has a 1MB cache, and your computation uses 6MB of data.

在1个处理器上，计算将在CPU，缓存和RAM之间进行大量数据移动.在8个处理器上，计算仅需在CPU和缓存之间移动数据.这样您就可以实现超线性加速.

On 1 processor the computation will be doing a lot of data movement between CPU, cache and RAM. On 8 processors the computation will only have to move data between CPU and cache. This way you can achieve super-linear speedup.

这些数字和此分析已简化，以供初学者使用.

These figures and this analysis have been simplified for exposition for a beginner.

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