Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!usc!apple!snorkelwacker.mit.edu!bloom-beacon!Achates.MIT.edu!jfc From: jfc@Achates.MIT.edu (John F Carr) Newsgroups: comp.unix.aix Subject: Re: '6000 performance issue Message-ID: <1990Nov21.233451.25121@athena.mit.edu> Date: 21 Nov 90 23:34:51 GMT References: <1990Nov19.042905.26880@i88.isc.com> <1131@nlsun1.oracle.nl> Sender: daemon@athena.mit.edu (Mr Background) Organization: Massachusetts Institute of Technology Lines: 12 In article <1131@nlsun1.oracle.nl> hbergh@oracle.nl (Herbert van den Bergh) writes: >This process currently has a data segment of 180Kb, of which about 100Kb is >never modified. You can imagine what performance improvement sharing this >data could give. AIX copies shared data pages when they are first accessed, not when they are first modified. Some may find this suprising, but it is a natural consequence of the memory management unit architecture. Unfortunately, the C compiler does not put objects declared "const" in read-only, shared storage. -- John Carr (jfc@athena.mit.edu)