Subject: Jerky system behavior.
To: None <>
From: Richard Rauch <>
List: port-amd64
Date: 03/03/2005 00:22:39
About August or so of last year, I upgraded from one -current to
another on my AMD64 box and suddenly started seeing a jerkiness to the
system.  Others reported it and I figured that it was a short-lived
kernel issue.  I recently did a new CVS update and built a fresh
kernel.  The problem is still there.

(I only recall AMD64 people remarking about it, so I assume that
it's AMD64-specific.)

Basically, somewhere on the order of each minute, one or more processes
freeze for about half a second, or perhaps a full second.

The system stability does not seem to be affected.

Not everything gets frozen.

Examples of things that have been affected:

 * bzflag (a game from pkgsrc).
 * emacs (text input, menus, making the cursor solid to indicate
   that it is the current window---this is under X, of course).
 * Remote access seems to also be affected sometimes (e.g.,
   shell commands, or a shell itself, while logged in via ssh).

By and large, the mouse cursor does not seem to be affected, so when
a process "freezes", I can still mouse around.  I just can't do anything
until things "unfreeze".

It *usually* happens when I am changing between windows or launching
a new shell command.  (But, as I noted, I also observe what appears
to be the same problem when playing a particular game continuously.)

I thought that this problem was pin-pointed as a VM issue and was fixed
months ago, but it persists in a -current kernel that I built on March 1
of this year.

Does anyone else see this?

(I haven't tried running 2.0 because of the IOAPIC issue that
renders a GENERIC kernel next to useless for me.  I guess I could
get a 2.0 checkout and make a custom release of that...generally I've
keped the HEAD tag checked out rather than specific releases.)

  "I probably don't know what I'm talking about."