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== Introduction ==
Multicore process are more prevalent now more than ever, and Multicore programming is essential to benefit from the power of the hardware as it allows to run our code different CPU cores. But it is very important to know and understand the underlying to fully utilize it. One of the most important system resources is the cache. And most architectures have shared cache lines. And this is why false sharing is a well know know problem in multicore/multithreaded processes. But first, '''What is False Sharing (aka cache line ping-ponging)anyways?''' <br>
False Sharing is one of the sharing pattern that affect performance when multiple threads share data. It arises when at least two threads modify or use data that happens to be close enough in memory that they end up in the same cache line. False sharing occurs when they constantly update their respective data in a way that the cache line migrates back and forth between two threads' caches.
In this article, we will look at some examples that demonstrate false sharing, tools to analyze false sharing, and the two coding techniques we can implement to eliminate false sharing.
=Cache Coherence=