Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!att!cbnewsh!dwc
From: dwc@cbnewsh.ATT.COM (Malaclypse the Elder)
Newsgroups: comp.unix.wizards
Subject: Re: Gripe about mickey-mouse VM behaviour on many Unixes
Keywords: MIPS, System-V, paging performance, working-set
Message-ID: <7453@cbnewsh.ATT.COM>
Date: 17 Jan 90 18:55:59 GMT
References: <1990Jan15.184042.7564@keysec.kse.com> <19821@watdragon.waterloo.edu> <130347@sun.Eng.Sun.COM>
Organization: The Legion of Dynamic Discord
Lines: 27

In article <130347@sun.Eng.Sun.COM>, lm@snafu.Sun.COM (Larry McVoy) writes:
> >Look, we all appreciate the tender loving care that VM architects have put
> >into strategies that are friendly to 100+ moderate-size processes context
> >switching rapidly in time-sharing mode.  But there are other ways to use
> >computers, and they are currently very poorly supported.  We paid for that
> >memory, we have a good use for it, and the OS is getting in our way, and it's
> >also REFUSING TO TELL US ACCURATELY WHAT'S GOING ON - an unforgiveable sin by
> >my Unix dogma.
> 
> Hmm.  The SunOS VM model was designed with exactly this in mind.  You can
> use damn near 100% of physical mem on a 4.0 or greater rev of the OS (the
> os uses some, but on a 32 meg machine you should be looking at close to
> 30 megs of user usable ram).
> 
actually, the vm model address using all of physical memory because
it has integrated the paging pool with the buffer pool.  but it really
hasn't done much for such things as page stealing.  in fact, on the
version that was ported into system v release 4, i believe it still uses the
two hand clock algorithm which goes through physical memory regardless
of what that page is being used for.  my studies have shown that you
really want to classify pages according to "type" even with reference
information.  i worked with some developers on prototyping some
improvements in the old regions architecture (system v release 3)
and maybe will get around to integrating it into the vm model.

danny chen
att!hocus!dwc