[Cerowrt-devel] hardware hacking on fq_codel in FPGA form at 10GigE

[Jim Gettys]

On Fri, Dec 21, 2012 at 1:25 PM, <dpreed at reed.com> wrote:

> I'm sure the HSPA+ modem is a binary blob.  For regulatory reasons, if
> nothing else...
>
>
>
> When I said open, I did not mean the ultimate ideal.  Hardware devices
> with firmware are often sold as black boxes.
>
>
>
> Fixing the bloat in HSPA+ and LTE systems will require organizations like
> Ericsson, ALU and Cisco and Huawei to get their acts together and fix their
> own bugs.
>

Actually, this needs probably/certainly needs help from the chip vendors as
well as the system vendors.  The system vendors (such as ALU) often get
their chips and drivers from those chip vendors.

I haven't looked into the HSPA+ or LTE systems; I am looking into DSL.  In
the DSL concrete example, Broadcom controls the bulk of the DSL chip
market, and (at least on the client home router end) provides a binary blob
Linux driver based on an antique Linux release (2.6.26, IIRC). The hardware
itself did not look like it had bad buffering, but the drivers....

I've been working with blogic (John Crispin) on debloating the Lantiq
driver, which we are trying to test; since it is entirely open source.  In
the Lantiq DSL driver case, the hardware sprouted exactly the same sort of
transmit/receive rings found in ethernet drivers, with the corresponding
bufferbloat due to device drivers being totally stupid.  Unfortunately, BQL
is ethernet only, and right now doesn't work properly at low bandwidths.

When John cut the transmit ring down to 2 packets, the latency dropped (at
the bandwidth he was testing at, .5Mbps) to around 60ms running fq_codel,
about what you would expect given the remaining buffers; we have to
automate the control of the transmit ring properly (since we probably do
need some help when running VDSL at 100Mbps).

I suspect/expect we'll find similar "features" when we dig into LTE and
HSPA+, though that is not certain.

Now, back to my saga of my recalcitrant water well, after which I can go
back to testing DSL the next trip to New Jersey (and flush the toilets and
have heat; I have geothermal heat...).
                         Sigh,
                                        - Jim



>
> -----Original Message-----
> From: "Jim Gettys" <jg at freedesktop.org>
> Sent: Friday, December 21, 2012 1:14pm
> To: "David P Reed" <dpreed at reed.com>
> Cc: "Dave Taht" <dave.taht at gmail.com>, "bloat-devel" <
> bloat-devel at lists.bufferbloat.net>, "cerowrt-devel at lists.bufferbloat.net"
> <cerowrt-devel at lists.bufferbloat.net>, "codel at lists.bufferbloat.net" <
> codel at lists.bufferbloat.net>
> Subject: Re: [Cerowrt-devel] hardware hacking on fq_codel in FPGA form at
> 10GigE
>
>
>
>
> On Fri, Dec 21, 2012 at 12:48 PM, <dpreed at reed.com> wrote:
>
>> And if you want an open tablet the ODROID U2 there is pretty nice for
>> <$900 all in, including an HSPA+ modem w/GPS.   I can only imagine what one
>> can do with this....
>>
> Often the modem bits are binary blobs.  Any information on this front?
> - Jim
>
>>
>>
>> -----Original Message-----
>> From: "Dave Taht" <dave.taht at gmail.com>
>> Sent: Friday, December 21, 2012 7:34am
>> To: dpreed at reed.com
>> Cc: "Hal Murray" <hmurray at megapathdsl.net>, "bloat-devel" <
>> bloat-devel at lists.bufferbloat.net>, codel at lists.bufferbloat.net,
>> cerowrt-devel at lists.bufferbloat.net
>> Subject: Re: [Cerowrt-devel] hardware hacking on fq_codel in FPGA form at
>> 10GigE
>>
>>   It really is astounding what is going on in the arm world:
>>
>>
>> http://www.hardkernel.com/renewal_2011/products/prdt_info.php?g_code=G135341370451
>>
>>
>>
>>
>> > The wndr3700v4 is out, and appears to be a good hardware upgrade from
>> > the 3800 series, but it's not supported by openwrt yet.
>> >
>> > I took a look at their GPL source distribution. And yea! it's openwrt.
>> > And boo! it's ancient openwrt, for example dnsmasq is 2.39 (current is
>> > 2.64), and their kernel is 2.6.31.
>> >
>> > I think the cpu and ethernet chips tho look a lot better: Atheros
>> > AR9344+ AR9580(5GHz)+AR9344(2.4GHz). It's my hope these do ipv6
>> > better.
>> >
>> > I have looked at similar products from buffalo and others, would like
>> > external antennas and a good switch this time around. Thoughts?
>> >
>> > --
>> > Dave Täht
>> >
>> > Fixing bufferbloat with cerowrt:
>> http://www.teklibre.com/cerowrt/subscribe.html
>>
>>
>>
>>
>>
>> --
>> Dave Täht
>>
>> Fixing bufferbloat with cerowrt:
>> http://www.teklibre.com/cerowrt/subscribe.html
>>
>>
>> _______________________________________________
>> Bloat-devel mailing list
>> Bloat-devel at lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/bloat-devel
>>
>>
>>
>>
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