Re: /srv/bzr/emacs/emacs-24 r111116: eval-after-load fix

[Stephen J. Turnbull]

Dmitry Gutov writes:
 > On 03.01.2013 7:27, Stephen J. Turnbull wrote:
 > > Glenn Morris writes:
 > >
 > >   > Maybe. (Personally, I doubt any of these purecopy calls have any
 > >   > non-negligible effect.)
 > >
 > > FWIW, XEmacs did away with purespace ages ago with no complaints from
 > > anybody.  (We still have `purecopy' for API compatibility with Emacs,
 > > but it's a no-op now.)
 > >
 > > That's damning with faint praise, of course, but it's a data point.
 > 
 > Is it really faint, though?

Yes, it is faint.  I have no numbers on comparative performance in
speed or size, and I wouldn't be surprised if it increases total
memory usage for some multi-xemacs-process cases (see Andreas's post).

The arguments that killed purespace for us were (1) most users
(including most of those who argued for keeping purespace :-) are in
one-xemacs-process-per-machine workflows, and (2) in theory modern
virtual memory management by OSes (we were specifically influenced by
Linux and Windows) should produce most of the benefits of purespace
anyway, since the dumped code contains only a few writable objects,
and those tend to be clumped on a very few pages per file, such that
the potentially written pages might be measured in 100s of KB out of
the 3-5 MB (at that time) of XEmacs memory.

I'm not sure I believe (2), though.

Steve