Short String optimization

[pepp]

@mcy

Has there been any discussion of having String live entirely on the stack for len < size_of::<usize>() * n ?

There have been some conversations in the past:

`String::as_mut_vec` prevents small string optimization

and

Small string optimization: remove as_mut_vec

I needed to create this thread, since I haven’t found too much dicussions on that topic. SSO is an important optimization in modern languages. To give an example: More than half of all allocations in the chromium browser are std::string allocations [1]. I don’t have a study or article around to prove the statement, but: You can easily imagine that many strings in applications won’t exceed a certain length. Storing those strings without allocating in the stack-object itself would be a huge gain …