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From: jpn@teddy.UUCP (John P. Nelson)
Newsgroups: comp.emacs
Subject: Re: GNU Emacs performance
Message-ID: <4041@teddy.UUCP>
Date: Tue, 26-May-87 14:21:22 EDT
Article-I.D.: teddy.4041
Posted: Tue May 26 14:21:22 1987
Date-Received: Thu, 28-May-87 03:53:49 EDT
References: <1439@arthur.cs.purdue.edu>
Reply-To: jpn@teddy.UUCP (John P. Nelson)
Organization: GenRad, Inc., Concord, Mass.
Lines: 17

>>Is GNU Emacs a CPU hog (at least relative to vi, for example)?
>Of course it is! But then, isn't vi a cpu hog relative to ed?

Well, I suspect that part of why GNU runs so slowly is:

  1.  Memory Usage.  GNU may do lots of paging on machines with small real
      real memory sizes.  First, the executable is large.  Also, EVERYTHING
      is kept in memory.  If you are editing a 3 Meg file, you need all 3 Meg
      IN (virtual) MEMORY at once.  Vi uses a temp file, and only keeps the
      active part of the file in memory.

  2.  Lisp code.  Significant parts of the GNU functionality is written
      in LISP.  Unfortunately, the LISP is interpreted, not compiled.
      For instance, several of our users here were using the C mode of
      GNU, and I noticed that those copies of emacs were using LOTS more
      cpu than users using the fundmental mode.  Other frequently used
      functions are written in LISP as well.