Receiving network data causes excessive consing

[Jesper Harder]

In GNU Emacs 21.3.50.21 (i686-pc-linux-gnu, GTK+ Version 2.0.2)
 of 2004-01-10 on defun.localdomain
configured using `configure '--with-gtk''

Hi!

I noticed that receiving data from a network process conses madly.
Here's a test case (it fetches the active list from news.gmane.org):

(let (m1 process)
    (with-current-buffer (get-buffer-create " *test*")
      (erase-buffer))
    (setq process (open-network-stream "test" " *test*" "news.gmane.org" 119))
    (setq m1 (memory-use-counts))
    (process-send-string process "LIST\n")
    (sit-for 50)
    (process-send-string process "QUIT\n")
    (mapcar* '- (memory-use-counts) m1))

=> (48055 3 0 0 509059 2 0 2063)

(with-current-buffer " *test*" (buffer-size))
=> 252123

I.e. it conses roughly two char-cells for every byte of data received!

I understand that it would be necessary to cons strings if the process
had process filters -- but it seems rather excessive without filters
where I would have thought that we could do without consing ...  I
also wonder why all those cons cells are created.

Emacs 20.5 seems to do a lot better[1] -- I get this result for the
same test:

  (4103 0 0 0 4168 0 0)


[1] I don't have Emacs 21 and 20.5 on the same box, though.  The
machine with 20.5 has a much faster network connection, and a
different architecture:

In GNU Emacs 20.5.1 (alphaev56-dec-osf4.0d, X toolkit)
 of Mon May 15 2000 on uniddec.uni-c.dk

configured using `configure --prefix=/usr/unic/share/emacs/20.5
--sharedstatedir=/usr/unic/share/emacs/20.5
--exec-prefix=/usr/unic/libexec/emacs/20.5
--x-libraries=/usr/X11R6/lib
--x-includes=/usr/X11R6/include:/usr/openwin/share/include --with-pop'