> At 7:08 PM -0400 7/26/01, Greg Kritsch wrote:
> >I understand there is an interrupt latency issue which 
> relates to ppp.
> >People should not assume that this explains all network and 
> serial port
> >problems.  As I understand it, the problem is with soft 
> interrupt delivery.
> >This does not affect "normal" usage, it ONLY affects kernel 
> implemented ppp.
> >Has anyone tried running a userland ppp implementation?
> 
> Would that "solve" the problem?  Wouldn't you just see the same 
> thing, plus some additional delays?

I have no idea, and my two G4s don't have anything I can run ppp on, so I
can't try it.  I suspect, from what I recall reading about the problem, that
it would change the problem behaviour at least, possibly solving it.  The
tun pseudo-interface would post the soft interrupt from outside any other
interrupt handler.

> In any case do you know if the problem is macppc-specific, or would 
> port-i386 see the same thing?  I have a modem on a 1.4.1 PC and am 
> seeing funny ping times.  Nothing for seconds and then a whole flood 
> of responses.  I suspect NetBSD because I get the same behavior with 
> several ISPs.  Will 1.5.1 make the problem go away?

Again, based on what I read about it here, it seemed to be a powerpc
specific problem.

I only mentioned anything at all because it seems many people are blaming
that problem for everything serial port related, and from what I read, it's
limited to affecting ppp because of the soft interrupt used for networking.
The hard interrupt for the serial ports should be working just fine.

> Cross my heart, strike me dead, stick a lobster on my head.
> John Crichton -- Farscape, 6/15/01
> h.b.hotz@jpl.nasa.gov, or hbhotz@oxy.edu

Gregory