CPU usage just having a big file aboard

CPU usage just having a big file aboard

[Dan Jacobson]

I noticed viewing a 2 MB file, the CPU meter would spring to life
every few seconds, even though it was in a long ago buried
buffer. Flyspell was off.  top(1) showed it munched quite a bit.
Must cause more often garbage collection or something.
Killing that buffer stopped it.  emacs21 21.3+1-9

Re: CPU usage just having a big file aboard

[Eli Zaretskii]

> From: Dan Jacobson <jidanni@jidanni.org>
> Date: Thu, 17 Mar 2005 02:22:34 +0800
> 
> I noticed viewing a 2 MB file, the CPU meter would spring to life
> every few seconds, even though it was in a long ago buried
> buffer. Flyspell was off.  top(1) showed it munched quite a bit.
> Must cause more often garbage collection or something.
> Killing that buffer stopped it.  emacs21 21.3+1-9

This is probably the sign of JIT Font-lock stealth fontification.
If so, this is normal.

Was JIT stealth fontification turned on in that buffer?

Re: CPU usage just having a big file aboard

[Richard Stallman]

    I noticed viewing a 2 MB file, the CPU meter would spring to life
    every few seconds, even though it was in a long ago buried
    buffer. Flyspell was off.  top(1) showed it munched quite a bit.
    Must cause more often garbage collection or something.
    Killing that buffer stopped it.  emacs21 21.3+1-9

How about if you run Emacs under GDB, and next time this occurs,
you could try to stop Emacs during that flurry of activity.
The backtrace will tell us what the activity is for.

You might have to try stopping it several times before you catch
it during the flurry of activity, but that won't be much work.