memory usage results (ack!)

[Wes Hardaker <wes@hardakers.net>]

Ok, so I upgraded my xemacs to 21.5.4 (the most recent beta) and
played with gnus for a while:

hardaker  1649 10.2 34.3 98716 87628 pts/2   S    16:53   3:32 xemacs
                         ^^^^^

nice nearly 100meg size.

This time, however, I compiled xemacs with memory debugging support.
Quickly tinking to figure out how to use it produces:

        (progn
          (mapcar (function (lambda (z)
        		      (insert (format "%s:\n" (buffer-name z)))
        		      (mapcar (function (lambda (x) (insert (format "  %s %s\n" (symbol-name (car x)) (cdr x))))) (buffer-memory-usage z))
        		      z)) (buffer-list t)))

The above prints memory usage stats for every buffer in xemacs.

Example output:

*scratch*:
  text 8216
  markers 1824
  extents 0
  other 512
  nil nil
  actually-requested 4357
  malloc-overhead 3921
  gap-overhead 2274
  dynarr-overhead 0

So, the text of the scratch buffer is small (8216), and the rest you
can guess it (I won't elaborate here).

So, sorting the entire output by sizes > 1M (using perl (gasp):

% perl -n -e '$x = $_ if (/:/); print $x, $_ if (/ \d{7}/);
 *nntpd*:
  text 34088184
 *nntpd*:
  actually-requested 29622319
 *nntpd*:
  gap-overhead 4365513
 *Gnus agent overview*:
  text 34088184
 *Gnus agent overview*:
  actually-requested 1181163
 *Gnus agent overview*:
  gap-overhead 32805805

Yikes.  Ok, so the nttpd buffer (note all these have a leading space)
is 34megs.  The agent overview is also 34 megs.  Double ouch.  What I
don't get is that the actual size of the buffer is much smaller (92097
of the latter) in, so the text field obviously isn't getting cleaned
up these days in either buffer.  But why?  So, lets be brave, save
this message buffer and kill both these buffers (not that it should
matter from a message sending point of view, but I don't remember how
well gnus deals with important deleted buffers).

Ahhh:
hardaker  1649  9.3 10.0 32332 25668 pts/2   S    16:53   3:53 xemacs
                         ^^^^^

So, the question is (especially for the emacs experts):  What's
happening with these two buffers and how do we fix it?

-- 
"Ninjas aren't dangerous.  They're more afraid of you than you are of them."