Subject: Weird load average
To: None <current-users@NetBSD.ORG>
From: Michael L. VanLoon -- <>
List: current-users
Date: 07/06/1996 00:57:14
Two things happened around the same time, that are causing really
weird load average results.  I don't know if this is NetBSD or XFree86
doing this, but I suspect it's XFree86.

1) I upgraded from 1.1-current just before it was converted to
1.2_Alpha, to a fairly current 1.2_Alpha.

2) I upgraded my ISA Mach8 card to a VLB Mach32.  Since I remembered
there was a bug in the Mach32 with certain line patters (would cause
the X server to hang), and I had gotten a couple hangs while I was
gone at work, or overnight (while XScreenSaver was running), I decided
to upgrade my XFree86-3.1.2 to 3.1.2E (the latest binary-only beta).

The weird thing is this: most of the time now I have a high load
average, usually somewhere between four and seven.  The load average
as reported by xload, top, and uptime/w are all consistent.  What's
weirder is that it will occasionally show a large dip, approaching
zero, then go back up (looking at xload, which can display several
minutes of load average).  But the weirdest thing is, I can't see
what's causing it!  The system doesn't seem sluggish like a process is
eating CPU.  And, both top and vmstat show the system is almost 100%
idle most of that time.  Vmstat also shows that zero processes are
running, blocked, or waiting during most of that time.

So, it appears there is a phantom process (or processes) that doesn't
really exist, that is blocking somewhere, raising load average, but
only virtually.

The reason I suspect it's related more to XFree86-3.1.2E is because I
think there was a small window of time where I was running newish
NetBSD current sources, before I had pulled in the 3.1.2E X server,
where I didn't see this behavior.  But I wasn't really paying
attention then (because I had no reason to expect this to start
happening), so I'm not totally sure.  I might try to run the 3.1.2 X
server with the 3.1.2E libraries, and hope it gives me some useful
info.  I suspect it won't run correctly, though.

My system is running just fine -- I don't have any problems with
operation in general.  I. e. everything is functioning O. K.  It's
just that this load average thing is kind of strange, and it just has
me curious.  Anyone have any clues on what might be going on?

  Michael L. VanLoon                       
        --<  Free your mind and your machine -- NetBSD free un*x  >--
    NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
        Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
    NetBSD ports in progress: PICA, others...

   Roll your own Internet access -- Seattle People's Internet cooperative.
                  If you're in the Seattle area, ask me how.