Path: utzoo!attcan!uunet!mcvax!ukc!stc!idec!marlow!fox
From: fox@marlow.uucp (Paul Fox)
Newsgroups: comp.unix.microport
Subject: Re: V.3 + top
Message-ID: <480@alice.marlow.uucp>
Date: 31 Oct 88 12:54:38 GMT
References: <468@alice.marlow.uucp> <10770006@hpcupt1.HP.COM>
Reply-To: fox@marlow.UUCP (Paul Fox)
Organization: Reuters Ltd PLC, Marlow, Bucks, England
Lines: 42

In article <10770006@hpcupt1.HP.COM> vandys@hpcupt1.HP.COM (Andrew Valencia(Seattle)) writes:
> ... Originally, being swapped out was virtually
>equated with moving the U area out of memory.  These days, a number of other
>things rank right up there with the U area.  Page tables, for instance.
>They tend to use even more space than U areas.  The U area's relationship
>to the actions of the VM system has become less dominating than it once
>was, as all manner of stuff gets heaped into the memory management picture.
>

Following on from my original posting, heres a status update.
Having got top to run I find that my system is 93% busy in the
kernel, EVEN WHEN ITS NOT DOING ANYTHING. After a number of weeks
of fretting and watching the appalling system response, I finally
resorted to removing DOS-MERGE from my kernel. And what do you know ?
I get normal system response times. Jeeze...

Anyway system response is still not too hot, but now I've modified top
to tell me what events sleeping processes are waiting on -- and I can
see that disk intensive processes are (quite rightly) waiting on
disk buffers, etc....

What I wanted to be able to do was print out how much of a process
was resident in memory. I've worked out some of the details --
scan the processes page directory and page table entries tosee which
pages are marked as present, but this approach would appear to be
potentially very CPU intensive - a process has 1024 page directory
tables * 1024 pages within each table. Although most of the address
space is sparse it would appear that I still need to scan the entirety
of these tables.

Does anyone know of a way of easily determining how much of a process
is resident, or of some other useful kernel quantity that can give
some idea of system response ?


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