Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!parcplace!khaw
From: khaw@parcplace.com (Mike Khaw)
Newsgroups: comp.lang.smalltalk
Subject: Re: performance question about ST80 v2.5 on MacII
Message-ID: <646@parcplace.com>
Date: 19 Dec 89 18:33:15 GMT
References: <1989Dec12.202546.11965@sdsu.edu> <63519@aerospace.AERO.ORG>
Distribution: usa
Organization: ParcPlace Systems, Mt. View, CA
Lines: 30

In article <1989Dec12.202546.11965@sdsu.edu> whitney@sdsu.sdsu.edu (Roger Whitney) writes:
>
>	I have been using Smalltalk-80 v2.3 from ParcPlace on a Macintosh II 
>computer with 5M of memory.  When I received my upgrade to v2.5 I noticed 
>a decrease in response of the windows. 
>1) Am I the only one that experiences this delay? Have I installed v2.5 
>incorrectly?
>
>	I assume that the delay is caused by compiling methods to native code 
>for the first time, after which it is stored in native-method zone. 

Dynamic translation overhead is normally imperceptible to the user.  On
the Mac, the main reason for the performance difference between 2.3 and
2.5 is the change from a 68000 assembler implementation to a C
implementation of the VM.  The VM's performance is only as good as the
code emitted by the MPW 3.0 C compiler.

>2) Does this means a similar delay occurs on other platforms? Is in 
>particular does this occur on Mac IIcx or Suns?

On Suns, you will notice a slight decline in speed, part of which is
because version 2.5 (and 2.4) only runs within a standard Sunview
window, whereas 2.3 could take over the screen.  Also, the standard VI
is somewhat larger, so on a system with not a lot of free RAM, version
2.5 is more likely to page than 2.3.  However, the overall change in
speed is not so noticeable on Suns as on the Mac.
-- 
Mike Khaw
ParcPlace Systems, Inc., 1550 Plymouth St., Mountain View, CA 94043
Domain=khaw@parcplace.com, UUCP=...!{uunet,sun,decwrl}!parcplace!khaw