使用自定义分配器来使用内存池而不是堆可能会很有用。这只是众多例子中的一个。

对于大多数情况，这肯定是一个不成熟的优化。但它在某些情况下(嵌入式设备、游戏等)非常有用。

使用自定义分配器来使用内存池而不是堆可能会很有用。这只是众多例子中的一个。

对于大多数情况，这肯定是一个不成熟的优化。但它在某些情况下(嵌入式设备、游戏等)非常有用。

在图形模拟中，我看到自定义分配器用于

std::allocator不直接支持的对齐约束。 通过为短期分配(只是这个框架)和长期分配使用单独的池来最小化碎片。

I personally use Loki::Allocator / SmallObject to optimize memory usage for small objects — it show good efficiency and satisfying performance if you have to work with moderate amounts of really small objects (1 to 256 bytes). It can be up to ~30 times more efficient than standard C++ new/delete allocation if we talk about allocating moderate amounts of small objects of many different sizes. Also, there's a VC-specific solution called "QuickHeap", it brings best possible performance (allocate and deallocate operations just read and write the address of the block being allocated/returned to heap, respectively in up to 99.(9)% cases — depends on settings and initialization), but at a cost of a notable overhead — it needs two pointers per extent and one extra for each new memory block. It's a fastest possible solution for working with huge (10 000++) amounts of objects being created and deleted if you don't need a big variety of object sizes (it creates an individual pool for each object size, from 1 to 1023 bytes in current implementation, so initialization costs may belittle the overall performance boost, but one can go ahead and allocate/deallocate some dummy objects before the application enters it's performance-critical phase(s)).

标准的c++ new/delete实现的问题是，它通常只是C malloc/free分配的包装器，它适用于较大的内存块，比如1024+字节。它在性能方面有显著的开销，有时还会占用额外的内存用于映射。因此，在大多数情况下，自定义分配器的实现方式是最大化性能和/或最小化分配小对象(≤1024字节)所需的额外内存量。

前一段时间我发现这个解决方案对我非常有用:STL容器的快速c++ 11分配器。它略微加快了VS2017上的STL容器(~5倍)以及GCC上的STL容器(~7倍)。它是一种基于内存池的特殊用途的分配器。它可以与STL容器一起使用，这多亏了您所要求的机制。

强制性链接到Andrei Alexandrescu 2015年CppCon关于分配者的演讲:

https://www.youtube.com/watch?v=LIb3L4vKZ7U

好处是，只是设计它们让你想到如何使用它们:-)