[Bloat] lwn.net's tcp small queues vs wifi aggregation solved

Jim Gettys jg at freedesktop.org
Mon Jun 25 20:52:08 EDT 2018


On Mon, Jun 25, 2018 at 8:44 PM Jonathan Morton <chromatix99 at gmail.com>
wrote:

> > On 26 Jun, 2018, at 3:36 am, Simon Barber <simon at superduper.net> wrote:
> >
> > Most hardware needs the packet finalized before it starts to contend for
> the medium (as far as I’m aware - let me know if you know differently). One
> issue is that if RTS/CTS is in use, then the packet duration needs to be
> known in advance (or at least mid point of the RTS transmission).
>
> This is a valid argument.  I think we could successfully argue for a delay
> of 1ms, if there isn't already enough data in the queue to fill an
> aggregate, after the oldest packet arrives until a request is issued.
>
> > If there are no other stations competing for airtime, why does it matter
> that we use two txops?
>
> One further argument would be power consumption.  Radio transmitters eat
> batteries for lunch; the only consistently worse offender I can think of is
> a display backlight, assuming the software is efficient.
> ​​
>
>
​No​t clear if this is true; we need current data.

In OLPC days, we measured the receive/transmit power consumption, and
transmit took essentially no more power than receive.  The dominant power
consumption was due to signal processing the RF, not the transmitter.  Just
listening sucked power....

Does someone understand what current 802.11 and actual chip sets consume
for power?

Jim


>  - Jonathan Morton
>
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