Re: [PATCH] mac80211: improve PID rate control mechanism by avoiding rate oscillation problem

[Felix Fietkau <nbd@openwrt.org>]

On 2012-02-29 1:14 PM, YIN Wei wrote:
> From: Wei YIN (Wei.Yin@nicta.com.au)
> 
> Improve PID rate control mechanism by solving the rate oscillation
> problem. Current PID mechanism is based on a PID  controller which
> tries to minimise the difference between the frame loss ratio (FLR)
> and the target FLR. Therefore it is straight forward that it increases
> to a higher rate when the FLR is less than the target without
> considering whether the higher rate can be supported. If the higher
> rate cannot be supported, significant FLR will occur, which causes the
> mechanism to decrease the rate sharply. The proposed approach only
> updates the rate when the proposed rate by the PID controller can
> achieve better throughput than the old rate. This patch applies to
> kernel 3.3.0.
> Signed-off-by: Wei YIN (Wei.Yin@nicta.com.au)
> ---
> diff -uprN wireless-testing_orig/net/mac80211/Kconfig
> wireless-testing/net/mac80211/Kconfig
> --- wireless-testing_orig/net/mac80211/Kconfig	2012-02-17
> 13:59:53.495254495 +1000
> +++ wireless-testing/net/mac80211/Kconfig	2012-02-21 11:35:40.495706869 +1000
> @@ -21,6 +21,7 @@ config MAC80211_HAS_RC
>  config MAC80211_RC_PID
>  	bool "PID controller based rate control algorithm" if EXPERT
>  	select MAC80211_HAS_RC
> +	default y
>  	---help---
>  	  This option enables a TX rate control algorithm for
>  	  mac80211 that uses a PID controller to select the TX
Several issues with this patch: line wrapping, weird encoding in the
comments: —
Also, please drop this change that alters the default value of
MAC80211_RC_PID.

- Felix