On Thu, May 28, 2020, 9:00 = AM <make-wifi-fast-request@lists.bufferb= loat.net> wrote:

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Today's Topics:

=C2=A0 =C2=A01. Re: REPOSTED: SmallNetBuilder Article: Does OFD= MA really
=C2=A0 =C2=A0 =C2=A0 work? Part 2 (Bob McMahon)
=C2=A0 =C2=A02. Re: REPOSTED: SmallNetBuilder Article: Does OFD= MA really
=C2=A0 =C2=A0 =C2=A0 work? Part 2 (Tim Higgins)
=C2=A0 =C2=A03. R7800 & openwrt and smallnetbuilder (Dave T= aht)

---------- Forwarded message ----------
From:=C2=A0Bob McMahon <bob.mcmahon@broad= com.com>
To:=C2=A0Tim Higgins <tim@smallnetbuilder.com>
Cc:=C2=A0Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>
Bcc:=C2=A0
Date:=C2=A0Wed, 27 May 2020 10:16:23 -0700
Subject:=C2=A0Re: [Make-wifi-fast] REPOSTED: SmallNetBuilder Article: Does OFDMA really work? Part 2

I would make a small packet run too. For iperf= 2 use -l 40 and -b 20000pps and vary the pps number. I would hope that OFDMA would increase this.=C2=A0

Also, don't forget=C2=A0about jitter - the derivative of late= ncy. Some protocols care more about jitter=C2=A0than they do laten= cy.

I'd look into measuring the actual=C2=A0latency and jitter of= the traffic vs using a ping as a proxy. This will be supported in iperf 2.0.14 using=C2=A0the write (server) side clock and --write-ack.=C2=A0 Better though is to synchronize the clocks= and use one way trip times. While I like to synchronize the realtime=C2=A0clocks to the GPS atomic clock as the reference= , using PTP and synchronizing=C2=A0to a common reference of any= PC oscillator may be good enough. PTP stats will give you errors and corrections and per the corrections one can get an idea of the error.

Thanks=C2=A0for posting. I really don't think OFDMA is going = to affect such large latencies in=C2=A0a noticeable manner. I th= ink it will be the ultra low latencies or near zero queuing that will matter.=C2=A0 For data center switches this is driven mo= stly by high frequency traders. For WiFi it's going to be newer games with VR/AR. Those latencies are going to need to be very low compared to today's use cases.

my $0.02,

Bob

On Wed, May 27, 2020 at= 7:37 AM Tim Higgins <tim@smallnetb= uilder.com> wrote:

Tests have been redone and article is back up. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D
Hi All,

This article uses the benchmark test described in Part 1 to test 6 Wi-Fi consumer routers. Results are not impressive.
https://www.smallnetbuilder.= com/wireless/wireless-features/33223-does-ofdma-really-work-part-2

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Tim

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---------- Forwarded message ----------
From:=C2=A0Tim Higgins <tim@smallnetbuilder.com>
To:=C2=A0Bob McMahon <bob.mcmahon@broadcom.com>
Cc:=C2=A0Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>
Bcc:=C2=A0
Date:=C2=A0Thu, 28 May 2020 10:22:04 -0400
Subject:=C2=A0Re: [Make-wifi-fast] REPOSTED: SmallNetBuilder Article: Does OFDMA really work? Part 2

= Hi Bob,

Thanks for the suggestions. The iper2 suggests are for UDP, correct?

As I said in the article, I'm done hunting this snark for now. Maybe others will take up the challenge.

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Tim

On 5/27/2020 1:16 PM, Bob McMahon wrote:

I would make a small packet run too. For iperf2 use -l 40 and -b 20000pps and vary the pps number. I would hope that OFDMA would increase this.=C2=A0=

Also, don't forget=C2=A0about jitter - the derivative of latency. Some protocols care more about jitter=C2=A0than = they do latency.

I'd look into measuring the actual=C2=A0latency and jitte= r of the traffic vs using a ping as a proxy. This will be supported in iperf 2.0.14 using=C2=A0the write (server) s= ide clock and --write-ack.=C2=A0 Better though is to synchron= ize the clocks and use one way trip times. While I like to synchronize the realtime=C2=A0clocks to the GPS atomic cl= ock as the reference, using PTP and synchronizing=C2=A0to a common reference of any PC oscillator may be good enough. PTP stats will give you errors and corrections and per the corrections one can get an idea of the error.

Thanks=C2=A0for posting. I really don't think OFDMA is go= ing to affect such large latencies in=C2=A0a noticeable manne= r. I think it will be the ultra low latencies or near zero queuing that will matter.=C2=A0 For data center switches = this is driven mostly by high frequency traders. For WiFi it's going to be newer games with VR/AR. Those latencies are going to need to be very low compared to today's use cases.

my $0.02,

Bob

On Wed, May 27, 202= 0 at 7:37 AM Tim Higgins <tim@smallnetbuilder.com&= gt; wrote:

Tests have been redone and article is back up.
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Hi All,

This article uses the benchmark test described in Part 1 to test 6 Wi-Fi consumer routers. Results are not impressive.
https://www.smallnetbuil= der.com/wireless/wireless-features/33223-does-ofdma-really-work-part-2

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Tim

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Make-wifi-fast@lists.bufferb= loat.net
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---------- Forwarded message ----------
From:=C2=A0Dave Taht <dave.taht@gmail.com>
To:=C2=A0Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>
Cc:=C2=A0
Bcc:=C2=A0
Date:=C2=A0Thu, 28 May 2020 08:28:05 -0700
Subject:=C2=A0[Make-wifi-fast] R7800 & openwrt and smallnetbuilder
I see that the R7800 is tim's goto router. I have one in a box... somewhere...

A benchmark between the stock R7800 firmware and openwrt 19.03=C2=A0 on it
would be nice to have. So far as I know
most of the offloads are in 19.03. However, the work ongoing on the
ath10k is pretty relevant, so A to B to C
would be a good shower of progress.

I figure tim is burned out totally on benchmarking wifi routers and is
off restoring his karma by planting a garden or hopefully something
relaxing like that(?), but I did manage to get most of my lab reassembled over the past few weeks.

--
"For a successful technology, reality must take precedence over public
relations, for Mother Nature cannot be fooled" - Richard Feynman

dave@taht.net= <Dave T=C3=A4ht> CTO, TekLibre, LLC Tel: 1-831-435-0729
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