Use Mmap to improve speed

[CyanChanges]

https://github.com/SUPERCILEX/fuc/blob/master/fuc_engine/src/ops/copy.rs#L526
Maybe we could use file Mmap to read write to files.
So we could bypass syscall overheads between read and writes.

[SUPERCILEX]

No, that's much slower. Writable file-backed mmaps are generally a bad idea as they work by marking pages a read-only, faulting them to writeable after marking them as dirty, and then flushing the page cache to disk on a timer. We use the copy_file_range, splice, sendfile, or plain read/write APIs as appropriate. These syscalls perform copies in the kernel and copy_file_range in particular can take advantage of copy acceleration provided by the file system (aka COW file systems).

Note that you must be using Rust 1.85 or above to get rust-lang/rust#134547.

[CyanChanges]

No, that's much slower. Writable file-backed mmaps are generally a bad idea as they work by marking pages a read-only, faulting them to writeable after marking them as dirty, and then flushing the page cache to disk on a timer. We use the copy_file_range, splice, sendfile, or plain read/write APIs as appropriate. These syscalls perform copies in the kernel and copy_file_range in particular can take advantage of copy acceleration provided by the file system (aka COW file systems).

Note that you must be using Rust 1.85 or above to get rust-lang/rust#134547.

Uhhh, I guess mmap might be faster only on Windows, since my friend uses mmap to write files, and It performs better than cpz somehow.

[SUPERCILEX]

Oh yeah cpz and rmz are only optimized for Linux so I'm sure we'll be easily beaten on Windows.