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From: Kalle Valo <kvalo@kernel.org>
To: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
Cc: <ath12k@lists.infradead.org>,  <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH 2/3] wifi: ath12k: Optimize the lock contention of used
 list in Rx data path
References: <20240226162310.629162-1-quic_periyasa@quicinc.com>
	<20240226162310.629162-3-quic_periyasa@quicinc.com>
Date: Mon, 11 Mar 2024 15:05:51 +0200
In-Reply-To: <20240226162310.629162-3-quic_periyasa@quicinc.com> (Karthikeyan
	Periyasamy's message of "Mon, 26 Feb 2024 21:53:09 +0530")
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Karthikeyan Periyasamy <quic_periyasa@quicinc.com> writes:

> When a packet arrives in Rx rings, the RX descriptor moves from the used
> list to the free list. Then, the rxdma ring gets replenished, where the Rx
> descriptor again moves from the free list to the used list. At the end, the
> descriptor came to the used list with unnecessary list movement. The
> descriptor used list is maintained in the Rxdma ring structure, which
> creates lock contention for the list operations (add, delete) in the Rx
> data path. Optimize the Rx data path by removing the used list from the
> common Rxdma ring and maintain as a local variable in the Rx ring handler
> itself, which avoid lock contention. Now, to find the used list descriptor
> during descriptor cleanup, we need to check the in_use flag for each Rx
> descriptor.
>
> Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
>
> Signed-off-by: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>

Before looking at this in detail: When optimising something it would be
good to have before and after numbers showing the improvement. Otherwise
it's just wishful thinking.

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