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Date: Fri, 29 Sep 2006 23:05:35 -0700
From: Paul Allen <pallen@ugcs.caltech.edu>
To: Kris Kennaway <kris@obsecurity.org>
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Sender: jd@ugcs.caltech.edu
Cc: freebsd-stable@freebsd.org, Craig Boston <craig@feniz.gank.org>
Subject: Re: CALL FOR TESTERS! [Re: 6.2 SHOWSTOPPER - em completely unusable
	on 6.2]
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>From Kris Kennaway <kris@obsecurity.org>, Fri, Sep 29, 2006 at 09:42:42PM -0400:
> On Fri, Sep 29, 2006 at 08:34:39PM -0500, Craig Boston wrote:
> > On Fri, Sep 29, 2006 at 08:19:04PM -0500, Craig Boston wrote:
> > > On Thu, Sep 28, 2006 at 01:48:42PM -0600, Scott Long wrote:
> > > > http://people.freebsd.org/~scottl/usb_fastintr_RELENG_6.diff
> > > 
> > > At first glance it appeared to work, but I'm about to do some more
> > > testing since I just discovered that I have to kldload something
> > > (anything) first in order to reproduce the problem.  Weird.
> > 
> > I can confirm that despite the other side effect I already mentioned,
> > this patch does fix or at least mask the problem I'm seing with em (and
> > probably usb).
> 
> Which is odd since the hypothesis Scott was working on should have
> shown up clearly in the mutex trace, but did not.

But it is consistent with there being a beat-frequency problem with 
respect to the scheduler.  I think the number you really need is not
how long giant was held but how long was spent waiting for it.


                                Paul