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Subject: Re: [RFC PATCH net-next v2 7/7] net: ravb: Use NAPI threaded mode on
 1-core CPUs with GbEth IP
To: Paul Barker <paul.barker.ct@bp.renesas.com>, "David S . Miller"
	<davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Jakub Kicinski
	<kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
CC: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>, Wolfram Sang
	<wsa+renesas@sang-engineering.com>, <netdev@vger.kernel.org>,
	<linux-renesas-soc@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20240206091909.3191-1-paul.barker.ct@bp.renesas.com>
 <20240206091909.3191-8-paul.barker.ct@bp.renesas.com>
From: Sergey Shtylyov <s.shtylyov@omp.ru>
Organization: Open Mobile Platform
Message-ID: <9ec29425-d66f-e808-52e3-7e4ce5cd79a5@omp.ru>
Date: Sat, 10 Feb 2024 22:00:03 +0300
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On 2/6/24 12:19 PM, Paul Barker wrote:

> NAPI Threaded mode (along with the previously enabled SW IRQ Coalescing)
> is required to improve network stack performance for single core SoCs
> using the GbEth IP (currently the RZ/G2L SoC family and the RZ/G3S SoC).
> 
> For the RZ/G2UL, network throughput is greatly increased by this change
> (results obtained with iperf3) for all test cases except UDP TX:
>   * TCP TX: 30% more throughput
>   * TCP RX: 9.8% more throughput
>   * UDP TX: 9.7% less throughput
>   * UDP RX: 89% more throughput
> 
> For the RZ/G3S we see improvements in network throughput similar to the
> RZ/G2UL.
> 
> The improvement of UDP RX bandwidth for the single core SoCs (RZ/G2UL &
> RZ/G3S) is particularly critical. NAPI Threaded mode can be disabled at
> runtime via sysfs for applications where UDP TX performance is a
> priority.
> 
> Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>

[...]

MBR, Sergey