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From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@kernel.org>
To: Felix Fietkau <nbd@nbd.name>, linux-wireless@vger.kernel.org
Cc: johannes@sipsolutions.net
Subject: Re: [RFC] mac80211: add AQL support for broadcast packets
In-Reply-To: <20240209184730.69589-1-nbd@nbd.name>
References: <20240209184730.69589-1-nbd@nbd.name>
Date: Sat, 10 Feb 2024 15:55:05 +0100
Message-ID: <87plx4s71y.fsf@toke.dk>
Precedence: bulk
MIME-Version: 1.0
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Felix Fietkau <nbd@nbd.name> writes:

> Excessive broadcast traffic with little competing unicast traffic can easily
> flood hardware queues, leading to throughput issues. Additionally, filling
> the hardware queues with too many packets breaks FQ for broadcast data.
> Fix this by enabling AQL for broadcast packets.
>
> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> ---
>  include/net/cfg80211.h     |  1 +
>  net/mac80211/debugfs.c     | 19 +++++++++++++++----
>  net/mac80211/ieee80211_i.h |  2 ++
>  net/mac80211/main.c        |  1 +
>  net/mac80211/sta_info.c    | 21 ++++++++++-----------
>  net/mac80211/tx.c          | 14 +++++++-------
>  6 files changed, 36 insertions(+), 22 deletions(-)
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index a499bd7e1def..2f280c629aea 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -3385,6 +3385,7 @@ enum wiphy_params_flags {
>  /* The per TXQ device queue limit in airtime */
>  #define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_L	5000
>  #define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_H	12000
> +#define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_BC	50000

How did you arrive at the 50 ms figure for the limit on broadcast
traffic? Seems like quite a lot? Did you experiment with different
values?

-Toke