Re: Removal of unexec support from glibc malloc

[Ali Bahrami <ali_gnu2@emvision.com>]

On 1/18/16 6:14 PM, Dmitry Gutov wrote:
> On 01/19/2016 01:45 AM, Ali Bahrami wrote:
>
>> Before you fight to to save unexec, I'd encourage you to measure the
>> impact, and see if it still matters.
>
> As a rough measurement, 'src/emacs -Q' takes ~0.5s to launch on my machine. 'src/temacs -Q` takes ~5.5s.
>
> It seems not only machines have become faster, Emacs has grown quite a bit, too. :)


    Maybe. I probably should have tried it before posting. :-)

Or maybe there are too many variables involved, and
comparing software from different decades usefully
is hard.

I just did that here, and my temacs -Q time is roughly
the same as yours. I wonder how much of that is simply finding
the files, opening them, and pulling in the bytes, and how
much is emacs loading those bytes into its internal data
structures? If it's mainly file I/O, then something that
gets those aggregated bytes into emacs quickly at startup,
but still requires emacs to go through them and load its
data structures might be nearly as fast.

Ways to do that might involve mmap, or having a teamcs-like
first stage write a C file containing a data array with the
compiled lisp bytecodes, which could then be compiled and
linked into a second stage emacs.

For that matter, I wonder how much time could be shaved
if temacs didn't announce each loaded file in the minibuffer
at startup?

- Ali