From: Rajkumar Manoharan <rmanohar@codeaurora.org>
To: "Toke Høiland-Jørgensen" <toke@toke.dk>
Cc: linux-wireless@vger.kernel.org,
make-wifi-fast@lists.bufferbloat.net,
Felix Fietkau <nbd@nbd.name>, Kan Yan <kyan@google.com>
Subject: Re: [PATCH RFC v5 3/4] mac80211: Add airtime accounting and scheduling to TXQs
Date: Tue, 09 Oct 2018 21:52:37 -0700 [thread overview]
Message-ID: <a65909ee425585a49d9e17f6504cf0ba@codeaurora.org> (raw)
In-Reply-To: <153908837900.9471.5394468800857658136.stgit@alrua-kau>
On 2018-10-09 05:32, Toke Høiland-Jørgensen wrote:
> This adds airtime accounting and scheduling to the mac80211 TXQ
> scheduler. A new callback, ieee80211_sta_register_airtime(), is added
> that drivers can call to report airtime usage for stations.
>
> When airtime information is present, mac80211 will schedule TXQs
> (through ieee80211_next_txq()) in a way that enforces airtime fairness
> between active stations. This scheduling works the same way as the
> ath9k
> in-driver airtime fairness scheduling. If no airtime usage is reported
> by the driver, the scheduler will default to round-robin scheduling.
>
> For drivers that don't control TXQ scheduling in software, a new API
> function, ieee80211_txq_may_transmit(), is added which the driver can
> use
> to check if the TXQ is eligible for transmission, or should be
> throttled to
> enforce fairness. Calls to this function must also be enclosed in
> ieee80211_txq_schedule_{start,end}() calls to ensure proper locking.
> TXQs
> that are throttled by ieee802111_txq_may_transmit() will be woken up
> again
> by a check added to the ieee80211_wake_txqs() tasklet.
>
Toke,
I am observing soft lockup issues again with this new series while
running
traffic with 50 clients. I am continuing testing with earlier series
along with
snippet I shared. When driver operates in pull-mode, throttled txqs are
marked
and refilled in airtime_tasklet. This is causing major throughput drops
and
packet loss and I am suspecting the latency in replenishing deficit.
Whereas in push-mode or in ath9k model, refill happens quicker at every
packet
indication as well as tx completion.
I am planning to get rid of tasklet completely as it is only meant for
pull-mode.
It would be better to refill in may_transmit() itself.
-Rajkumar
next prev parent reply other threads:[~2018-10-10 4:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-09 12:32 [PATCH RFC v5 0/4] Move TXQ scheduling and airtime fairness into mac80211 Toke Høiland-Jørgensen
2018-10-09 12:32 ` [PATCH RFC v5 2/4] cfg80211: Add airtime statistics and settings Toke Høiland-Jørgensen
2018-10-09 12:32 ` [PATCH RFC v5 1/4] mac80211: Add TXQ scheduling API Toke Høiland-Jørgensen
2018-10-09 12:32 ` [PATCH RFC v5 4/4] ath9k: Switch to mac80211 TXQ scheduling and airtime APIs Toke Høiland-Jørgensen
2018-10-09 12:32 ` [PATCH RFC v5 3/4] mac80211: Add airtime accounting and scheduling to TXQs Toke Høiland-Jørgensen
2018-10-10 4:52 ` Rajkumar Manoharan [this message]
2018-10-10 11:15 ` Toke Høiland-Jørgensen
2018-10-10 23:20 ` Rajkumar Manoharan
2018-10-11 10:38 ` Toke Høiland-Jørgensen
2018-10-12 7:38 ` Rajkumar Manoharan
2018-10-12 10:16 ` Toke Høiland-Jørgensen
2018-10-16 7:07 ` Rajkumar Manoharan
2018-10-16 10:20 ` Toke Høiland-Jørgensen
2018-10-13 7:09 ` [Make-wifi-fast] " Dave Taht
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