From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-iy0-f171.google.com (mail-iy0-f171.google.com [209.85.210.171]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 39C46201A5A for ; Sun, 29 May 2011 10:54:09 -0700 (PDT) Received: by iyi20 with SMTP id 20so3887745iyi.16 for ; Sun, 29 May 2011 11:10:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=EitdM4R6dxkss00tlxKOBlnmEzAHWbD4PcJta5C7gQ0=; b=WGl6BFbUSk1TNA+qKc8m/vvO1ZdyxuGhfdhQ49bLuM4eAow5MIJ7EW3UTkVqlhhnny tRg3x+sCsW2Re33gbP+/z9UBJHLkpgtGccbICSfZ21PfkVhmwzl21nVHceHFEfdjGFx2 +tdoVSIw5TLcfDKADiezOFYT57c8775d7yFbQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=TUjm7EJFhXcSnRxKFFn1GwHLNzZMVe5nD/LLS5GuHwX4bDQuos/NUnzzFPCgAV8ga4 Ck33X7VSAWA61ffyUF6QIvD+B8hlZP0JBLTjMZBqt9DhROUgN0rurLaYwSs3i16JS1uh JjNTkKcEn0fFv8UnzaU1YY3itYkgNPsNq02Hk= MIME-Version: 1.0 Received: by 10.42.40.129 with SMTP id l1mr6281998ice.225.1306692600208; Sun, 29 May 2011 11:10:00 -0700 (PDT) Received: by 10.231.39.203 with HTTP; Sun, 29 May 2011 11:10:00 -0700 (PDT) In-Reply-To: <20110524145014.GA2504@tuxdriver.com> References: <20110524145014.GA2504@tuxdriver.com> Date: Sun, 29 May 2011 12:10:00 -0600 Message-ID: Subject: Re: still coping with zero packet loss over wireless From: Dave Taht To: "John W. Linville" Content-Type: multipart/alternative; boundary=90e6ba6e8a3c441d4b04a46e14ba Cc: bloat-devel@lists.bufferbloat.net X-BeenThere: bloat-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: "Developers working on AQM, device drivers, and networking stacks" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 May 2011 17:54:09 -0000 --90e6ba6e8a3c441d4b04a46e14ba Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Tue, May 24, 2011 at 8:50 AM, John W. Linville w= rote: > 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 second= s > 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 th= at > > 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 proble= m with debugfs root@io:/sys/kernel/debug# cat ./ieee80211/phy0/netdev:wlan2/stations/ce:3d:c7:b0:ae:78/tx_retry_count 291 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 > -- > John W. Linville Someday the world will need a hero, and y= ou > linville@tuxdriver.com might be all we have. Be ready. > --=20 Dave T=E4ht SKYPE: davetaht US Tel: 1-239-829-5608 http://the-edge.blogspot.com --90e6ba6e8a3c441d4b04a46e14ba Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable


On Tue, May 24, 2011 at 8:50 AM, Joh= n W. Linville <linville@tuxdriver.com> 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 - re= duced
> 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 secon= ds to
> complete, and zero packet loss until I moved completely out of range o= f 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 t= hat
> I've missed, in getting packets to actually fail in 10s of ms?

Not one of which I am aware. =A0That sort of thing is going to depend=
quite a bit on the hardware itself, and it's driver. =A0Maybe some
ath9k folk can comment?


I finally got out from under enough to have a cha= nce to look at this problem with debugfs

root@io:/sys/kernel/debug# cat ./ieee80211/phy0/netdev:wlan2/stations/ce:3d= :c7:b0:ae:78/tx_retry_count
291

My assumption is that this is not the value for retries, but the total numb= er of times a given station has had to retry.
=A0
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
--
John W. Linville =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Someday the world will need= a hero, and you
linville@tuxdriver.com =A0 = =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0might be all we have. =A0Be ready.



--
Dave T=E4ht
S= KYPE: davetaht
US Tel: 1-239-829-5608
http://the-edge.blogspot.com
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