still coping with zero packet loss over wireless

Dave Taht dave.taht at
Sun May 29 11:10:00 PDT 2011

On Tue, May 24, 2011 at 8:50 AM, John W. Linville <linville at>wrote:

> On Tue, May 24, 2011 at 02:46:59PM +0000, Dave Taht wrote:
> > yesterday I finally got a chance to move a few dozen meters out of the
> lab
> > and test the latest build of uberwrt "capetown" and debloat-testing.
> >
> > I'd hoped with the debloating techniques in place in capetown - reduced
> > buffers (4), reduced sw retries (2), hw retries (2, or so I thought) I'd
> > actually see some packet loss.
> >
> > and what I saw instead, was pings that would take as long as 1.6 seconds
> to
> > complete, and zero packet loss until I moved completely out of range of
> the
> > router.
> >
> > I never thought it would be so hard to lose a packet in my life!
> >
> > Is there some system tunable, somewhere, in the linux wireless stack that
> > I've missed, in getting packets to actually fail in 10s of ms?
> Not one of which I am aware.  That sort of thing is going to depend
> quite a bit on the hardware itself, and it's driver.  Maybe some
> ath9k folk can comment?
I finally got out from under enough to have a chance to look at this problem
with debugfs

root at io:/sys/kernel/debug# cat

My assumption is that this is not the value for retries, but the total
number of times a given station has had to retry.

Is there anything useful that I can poke around in down here?

(I'd actually gone into this to see if I could pull more info out on the
ag71xx issue on the other thread)

> --
> John W. Linville                Someday the world will need a hero, and you
> linville at                  might be all we have.  Be ready.

Dave Täht
SKYPE: davetaht
US Tel: 1-239-829-5608
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