Re: immediate strings #2

[Dmitry Antipov <antipov@mvista.com>]

On 11/28/2011 09:33 PM, Stefan Monnier wrote:

> It's great to see that it can speed up compilation, tho (although
> the 1.3% difference could just as well be due to noise).

This noise is quite repetitive, and it should be even more repetitive
and visible after fitting Lisp_String within 32 (or 16, on 32-bit) bytes.

> You might want to check what proportion of those strings have a
> NULL `intervals' field.

I believe it's typical to have 20-50 intervals for 10000 strings, so
it's worth trying to store string intervals separately (in a kind
of hash table, for example). On the other side, there is a reason to
have extra sizeof(void *) bytes at the beginning of Lisp_String - to
use by NEXT_FREE_LISP_STRING.

Dmitry