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References: <20210209070755.23019-1-pkshih@realtek.com> <20210209070755.23019-4-pkshih@realtek.com>
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From:   Brian Norris <briannorris@chromium.org>
Date:   Thu, 11 Feb 2021 19:44:43 -0800
Message-ID: <CA+ASDXN_TgaHvbthz-SqHdjrmRHVpEag9+sQWkGcivNFv94GAA@mail.gmail.com>
Subject: Re: [PATCH v5 3/8] rtw88: add napi support
To:     Ping-Ke Shih <pkshih@realtek.com>
Cc:     Yan-Hsuan Chuang <tony0620emma@gmail.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        Bernie Huang <phhuang@realtek.com>
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On Mon, Feb 8, 2021 at 11:11 PM Ping-Ke Shih <pkshih@realtek.com> wrote:
>
> From: Po-Hao Huang <phhuang@realtek.com>
>
> Use napi to reduce overhead on rx interrupts.
>
> Driver used to interrupt kernel for every Rx packet, this could
> affect both system and network performance. NAPI is a mechanism that
> uses polling when processing huge amount of traffic, by doing this
> the number of interrupts can be decreased.
>
> Network performance can also benefit from this patch. Since TCP
> connection is bidirectional and acks are required for every several
> packets. These ack packets occupie the PCI bus bandwidth and could
> lead to performance degradation.
>
> When napi is used, GRO receive is enabled by default in the mac80211
> stack. So mac80211 won't pass every RX TCP packets to the kernel TCP
> network stack immediately. Instead an aggregated large length TCP packet
> will be delivered.
>
> This reduces the tx acks sent and gains rx performance. After the patch,
> the Rx throughput increases about 25Mbps in 11ac.
>
> Signed-off-by: Po-Hao Huang <phhuang@realtek.com>
> Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>

I think this version handles my review comments and straightens up the
locking situation:

Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>

Thanks.