From: Sebastian Gottschall <s.gottschall@dd-wrt.com>
To: Rajkumar Manoharan <rmanohar@codeaurora.org>,
Johannes Berg <johannes@sipsolutions.net>
Cc: Felix Fietkau <nbd@nbd.name>,
linux-wireless@vger.kernel.org,
linux-wireless-owner@vger.kernel.org
Subject: Re: [RFC] mac80211: add a function for running rx without passing skbs to the stack
Date: Thu, 30 Jul 2020 16:02:18 +0200 [thread overview]
Message-ID: <b7943d1e-0e1e-c72e-14c6-c783058f089a@dd-wrt.com> (raw)
In-Reply-To: <801c3763d82b86268797fdc75040ce75@codeaurora.org>
Am 29.07.2020 um 03:47 schrieb Rajkumar Manoharan:
> On 2020-07-25 12:14, Johannes Berg wrote:
>>> +void ieee80211_rx_napi(struct ieee80211_hw *hw, struct
>>> ieee80211_sta *pubsta,
>>> + struct sk_buff *skb, struct napi_struct *napi)
>>> +{
>>> + struct sk_buff_head list;
>>> +
>>> + __skb_queue_head_init(&list);
>>> +
>>> + /*
>>> + * key references and virtual interfaces are protected using RCU
>>> + * and this requires that we are in a read-side RCU section during
>>> + * receive processing
>>> + */
>>> + rcu_read_lock();
>>> + ieee80211_rx_list(hw, pubsta, skb, &list);
>>> + rcu_read_unlock();
>>> +
>>> + while ((skb = __skb_dequeue(&list)) != NULL)
>>
>> I'd drop the != NULL, but no strong feelings :)
>>
>>> + if (napi)
>>> + napi_gro_receive(napi, skb);
>>> + else
>>> + netif_receive_skb(skb);
>>
>> Nit: I'd prefer braces on the loop, just makes it nicer to read IMHO.
>>
>> OTOH, the !napi case should use netif_receive_skb_list(), no?
>>
>> Given the discussion, it also seems a bit odd to add more work for NAPI
>> poll where we process one by one ... But I see why you did that, and I
>> guess it's not actually that much more work.
>>
> IIUC Sebastian mentioned that threadable NAPI approach is helping in
> load balancing
> with minor check for dummy netdev for wireless drivers. Does this
> change improve
> the latency in both threaded and non-threaded modes?
check also for felix's last variant. he made a different patch based on
workq's
i'm testing this variant now on various platforms including a patched
ath10k driver
next step would be just to change other wifi drivers for the same
concept. just a few are using napi at all (mt76, ath10k and iwlwifi)
>
> -Rajkumar
>
prev parent reply other threads:[~2020-07-30 14:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-25 18:55 [RFC] mac80211: add a function for running rx without passing skbs to the stack Felix Fietkau
2020-07-25 19:14 ` Johannes Berg
2020-07-29 1:47 ` Rajkumar Manoharan
2020-07-29 1:56 ` Rajkumar Manoharan
2020-07-30 14:02 ` Sebastian Gottschall [this message]
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