Re: Jerky system behavior.

On Thu, 3 Mar 2005 00:22:39 -0600, Richard Rauch <rkr@xxxxxxxx> wrote:
> 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 don't know if this helps, but I'm pretty sure I don't see this on
the release-2 branch. Doesn't cron check the tab once a minute?
Anything else that happens once a minute?  Is it that regular though?

Andy