复制时使用的理想内存块大小是多少？ [英] What is the ideal memory block size to use when copying?

问题描述

我目前使用每个内存块100 MB来复制大型文件。

I am currently using 100 megabytes per memory block to copy large files.

人们通常使用的好数量是多少？

Is there a "good" amount that people normally use?

编辑

感谢所有伟大的回应。

我对这些概念还是很新的，所以我将尝试理解很多已经说过的（例如回写缓存）。我不断学习新的东西：）

I'm still quite new to these concepts so I'll try to understand a lot of the ones that have been said (e.g. write back cache). I keep learning new things :)

推荐答案

4096和32KB之间的块是典型的选择。使用100MB是反作用的。您正在占用RAM缓冲区，可以更好地用作文件系统回写缓存。

A block between 4096 and 32KB is the typical choice. Using 100MB is counter-productive. You are occupying RAM with the buffer that can be put to much better use as the file system writeback cache.

复制文件非常快该文件完全适合缓存，WriteFile（）调用是一个简单的内存到内存的副本。然后缓存管理器会将它写入磁盘。但是当缓存中没有更多的空间时，当WriteFile（）必须等待空间可用时，复制速度会下降。现在它以磁盘写入速度。

Copying files is very fast when the file fits completely in the cache, the WriteFile() call is a simple memory-to-memory copy. The cache manager then lazily writes it out to the disk. But when there's no more room in the cache, the copy speed drops off a cliff when WriteFile() has to wait for space to be made available. It now goes at disk write speeds.

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