Re: [Emacs-diffs] /srv/bzr/emacs/trunk r109157: Compact buffers when idle.

[Dmitry Antipov <dmantipov@yandex.ru>]

On 07/19/2012 03:54 PM, Stefan Monnier wrote:

> I can't think of any case where that would provide any noticeable
> benefit (whereas I can think of cases where it just wastes resources).

Hm... I expect this to be something exotic, like replace-string
across hundreds of buffers. On the other side, it's quite
typical code refactoring operation. When I need to change function
name across the project, I'm using perl just because Emacs is too slow :-(.

> The GC is run fairly regularly, also typically while idle, and does the
> compaction.

1. Typically it happens when we're executing byte code, or from eval.c,
    when we want to be as fast as possible.

2. I don't understand why idle call to Fgarbage_collect is glued with
    auto-save-timeout. If I don't want to use auto-save, why I shouldn't
    call GC when idle?

> So until you can provide some concrete and convincing numbers that show
> some benefit, I'd ask you to remove that pat of your patch.

Hm... I suppose that 3GHz CPUs makes a lot of small optimizations almost
invisible; but I believe it doesn't mean that they're not needed anymore.
For example, I'm pretty sure that removing Blength bytecode (and so calling
Flength via Funcall) will not introduce any noticeable slowdown for any
real use case (although we can design special benchmark which will
do myriads of (length xxx) and nothing more).

Dmitry