From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qa0-x234.google.com (mail-qa0-x234.google.com [IPv6:2607:f8b0:400d:c00::234]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id F235321F17D for ; Tue, 25 Feb 2014 05:10:10 -0800 (PST) Received: by mail-qa0-f52.google.com with SMTP id j15so319100qaq.39 for ; Tue, 25 Feb 2014 05:10:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:content-type:message-id:mime-version:subject:date:references :to:in-reply-to; bh=y8YH09Ey93Af7CAXQ3ukgH9vUIq1Qe0APvMOZMBySfg=; b=qYysAyGDNL8JpOUkAhGmsve/xYwGsnmrbA3toDlVuw/lXkJIRckpuzRyztr+YTRp+4 QWiQMKzvlinlYyMb3iigk/g/tsfEZlVqKrWHCceTGOMC+DLTURO7MUf7hNjpzYU0NTMv kCtO4SkrO1JjMR1PXrB5D+mZ0lmyHTm129PiL+EK6GVh3zIv0doOJ+lcnEewmCuFPOFq X6axdcRyQMCvhvlEwwOSbWeNkggxWpL6fmUB+G+tDxlVQl+93PFmITg8Qu5ztMBsbkPQ rYH2IyBr0SV2jmAU5Pv2Tv30nDuledpejXRfc5suAm6scXcmpb8eJPJ5+UTpk+qHsmLo DYew== X-Received: by 10.224.119.199 with SMTP id a7mr37928253qar.27.1393333809654; Tue, 25 Feb 2014 05:10:09 -0800 (PST) Received: from richs-mbp-3513.home.lan (pool-72-73-76-141.ptldme.east.myfairpoint.net. [72.73.76.141]) by mx.google.com with ESMTPSA id u1sm59127747qac.1.2014.02.25.05.10.08 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 25 Feb 2014 05:10:09 -0800 (PST) From: Rich Brown Content-Type: multipart/alternative; boundary="Apple-Mail=_889FCFCA-371E-481F-80E0-17A5B7793CB2" Message-Id: Mime-Version: 1.0 (Mac OS X Mail 7.1 \(1827\)) Date: Tue, 25 Feb 2014 08:09:53 -0500 References: <4E5BC321-2054-4364-BECC-DF34E0D20380@gmail.com> To: cerowrt-devel In-Reply-To: X-Mailer: Apple Mail (2.1827) Subject: Re: [Cerowrt-devel] Equivocal results with using 3.10.28-14 X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 Feb 2014 13:10:11 -0000 --Apple-Mail=_889FCFCA-371E-481F-80E0-17A5B7793CB2 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 Thanks everyone for all the good advice. I will summarize my responses = to all your notes now, then I'll go away and run more tests. - Yes, I am using netperf 2.6.0 and netperf-wrapper from Toke's github = repo. - The "sync rate" is the speed with which the DSL modem sends bits = to/from my house. I got this by going into the modem's admin interface = and poking around. (It turns out that I have a very clean line, high = SNR, low attenuation. I'm much less than a km from the central office.) = So actual speed should approach this, except... - Of course, I have to subtract all those overheads that Sebastian = described - ATM 48-in-53, which knocks off 10%; ATM frame overhead which = could add up to 47 bytes padding to any packet, etc.) - I looked at the target calculation in Dave's Home Gateway best = practices. = (http://snapon.lab.bufferbloat.net/~d/draft-taht-home-gateway-best-practic= es-00.html) Am I correct that it sets the target to five 1500-byte = packet transmission time or 5 msec, whichever is greater? - I was astonished by the calculation of the bandwidth consumed by acks = in the reverse direction. In a 7mbps/768kbps setting, I'm going to lose = one quarter of the reverse bandwidth? Wow! - I wasn't entirely clear how to set the target in the SQM GUI. I = believe that "target ##msec" is an acceptable format. Is that correct? - There's also a discussion of setting the target with "auto", but I'm = not sure I understand the syntax. Now to find some time to go back into the measurement lab! I'll report = again when I have more data. Thanks again. Rich On Feb 24, 2014, at 9:56 AM, Aaron Wood wrote: > Do you have the latest (head) version of netperf and netperf-wrapper? = some changes were made to both that give better UDP results. >=20 > -Aaron >=20 >=20 > On Mon, Feb 24, 2014 at 3:36 PM, Rich Brown = wrote: >=20 > CeroWrt 3.10.28-14 is doing a good job of keeping latency low. But... = it has two other effects: >=20 > - I don't get the full "7 mbps down, 768 kbps up" as touted by my DSL = provider (Fairpoint). In fact, CeroWrt struggles to get above 6.0/0.6 = mbps. >=20 > - When I adjust the SQM parameters to get close to those numbers, I = get increasing levels of packet loss (5-8%) during a concurrent ping = test. >=20 > So my question to the group is whether this behavior makes sense: that = we can have low latency while losing ~10% of the link capacity, or that = getting close to the link capacity should induce large packet loss... >=20 > Experimental setup: >=20 > I'm using a Comtrend 583-U DSL modem, that has a sync rate of 7616 = kbps down, 864 kbps up. Theoretically, I should be able to tell SQM to = use numbers a bit lower than those values, with an ATM plus header = overhead with default settings. >=20 > I have posted the results of my netperf-wrapper trials at = http://richb-hanover.com - There are a number of RRUL charts, taken with = different link rates configured, and with different link layers. >=20 > I welcome people's thoughts for other tests/adjustments/etc. >=20 > Rich Brown > Hanover, NH USA >=20 > PS I did try the 3.10.28-16, but ran into troubles with wifi and = ethernet connectivity. I must have screwed up my local configuration - I = was doing it quickly - so I rolled back to 3.10.28.14. > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel >=20 --Apple-Mail=_889FCFCA-371E-481F-80E0-17A5B7793CB2 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 Thanks = everyone for all the good advice. I will summarize my responses to all = your notes now, then I'll go away and run more = tests.

- Yes, I am using netperf 2.6.0 and = netperf-wrapper from Toke's github repo.

- The = "sync rate" is the speed with which the DSL modem sends bits to/from my = house. I got this by going into the modem's admin interface and poking = around. (It turns out that I have a very clean line, high SNR, low = attenuation. I'm much less than a km from the central office.) So actual = speed should approach this, except...

- Of = course, I have to subtract all those overheads that Sebastian described = - ATM 48-in-53, which knocks off 10%; ATM frame overhead which could add = up to 47 bytes padding to any packet, etc.)

- I = looked at the target calculation in Dave's Home Gateway best practices. = (http://snapon.lab.bufferbloat.net/~d/draft-taht-home-ga= teway-best-practices-00.html) Am I correct that it sets the target = to five 1500-byte packet transmission time or 5 msec, whichever is = greater?

- I was astonished by the calculation = of the bandwidth consumed by acks in the reverse direction. In a = 7mbps/768kbps setting, I'm going to lose one quarter of the reverse = bandwidth? Wow!

- I wasn't entirely clear how = to set the target in the SQM GUI. I believe that "target ##msec" is an = acceptable format. Is that correct?

- There's = also a discussion of setting the target with "auto", but I'm not sure I = understand the syntax.

Now to find some time to = go back into the measurement lab! I'll report again when I have more = data. Thanks = again.

Rich



On Feb 24, 2014, at 9:56 AM, Aaron Wood = <woody77@gmail.com> = wrote:

Do you have the latest (head) version of = netperf and netperf-wrapper?  some changes were made to both that = give better UDP results.

-Aaron


On Mon, Feb 24, 2014 at 3:36 PM, Rich Brown <richb.hanover@gmail.com> = wrote:

CeroWrt 3.10.28-14 is = doing a good job of keeping latency low. But... it has two other = effects:

- I don't get the full "7 mbps down, 768 kbps up" as touted by my DSL = provider (Fairpoint). In fact, CeroWrt struggles to get above 6.0/0.6 = mbps.

- When I adjust the SQM parameters to get close to those numbers, I get = increasing levels of packet loss (5-8%) during a concurrent ping = test.

So my question to the group is whether this behavior makes sense: that = we can have low latency while losing ~10% of the link capacity, or that = getting close to the link capacity should induce large packet = loss...

Experimental setup:

I'm using a Comtrend 583-U DSL modem, that has a sync rate of 7616 kbps = down, 864 kbps up. Theoretically, I should be able to tell SQM to use = numbers a bit lower than those values, with an ATM plus header overhead = with default settings.

I have posted the results of my netperf-wrapper trials at http://richb-hanover.com - There are a number of = RRUL charts, taken with different link rates configured, and with = different link layers.

I welcome people's thoughts for other tests/adjustments/etc.

Rich Brown
Hanover, NH USA

PS I did try the 3.10.28-16, but ran into troubles with wifi and = ethernet connectivity. I must have screwed up my local configuration - I = was doing it quickly - so I rolled back to 3.10.28.14.
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