![]() FastMM was a great improvement over the previous Delphi memory manager and, although it does not perform perfectly in the parallel programming world, it still functions very well after more than ten years. It was written as an open source memory manager by Pierre LeRiche with help from other Delphi programmers and was later licensed by Borland. From Delphi 2006, this memory manager is called FastMM. To move from hypothetical to specific, Delphi also includes such a memory manager. ![]() The next time the application would request some memory (30 bytes for example), the internal memory manager would get that memory from the same 4,096-byte block. In a hypothetical scenario, the internal memory manager would request 4,096 bytes from the operating system and give 20 bytes of that to the application. It still requests memory from the operating system but then splits it internally into multiple parts. When you request 20 bytes of memory, the request goes to that internal memory manager. To fix these and other problems, programming languages typically implement their own internal memory management algorithms. In other words, 4,076 bytes would be wasted. For example, if you call Windows’ VirtualAlloc function to get 20 bytes of memory, it will actually reserve 4 KB (or 4,096 bytes) for you. In lots of cases, a memory system also doesn’t know how to return small chunks of memory. Slicing and dicing memory straight from the operating system is a relatively slow operation. The article is an excerpt from a book written by Primož Gabrijelčič, titled Delphi High Performance. In this tutorial, we will touch upon memory management techniques, the most prime factor in parallel programming. When an object is not needed anymore, that memory can be returned to the loving care of the operating system. When a program needs some memory, for example, to create an object, it can ask the operating system and it will give it a slice of shared memory. Multiple programs must coexist inside a limited memory space, and that can only be possible if the operating system is taking care of it. ![]() Memory management is part of practically every computing system. ![]()
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