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Subject: Re: [RFC PATCH net-next v2 0/7] Improve GbEth performance on Renesas
 RZ/G2L and related SoCs
From: Sergey Shtylyov <s.shtylyov@omp.ru>
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>
 <29d9d3cb-4ac2-32e2-51b8-475d34216b07@omp.ru>
 <99a883c8-ccf2-4e52-9c34-ead59cd84117@bp.renesas.com>
 <4bf96e67-d35b-813c-ac9b-f2094903ac55@omp.ru>
Organization: Open Mobile Platform
Message-ID: <7923894a-c42c-b4ae-1828-775d1fb68a10@omp.ru>
Date: Tue, 13 Feb 2024 12:38:41 +0300
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On 2/12/24 11:53 PM, Sergey Shtylyov wrote:
[...]

>>>> This series aims to improve peformance of the GbEth IP in the Renesas
>>>
>>>    You didn't fix the typo in "peformance"... :-/
>>>
>>>> RZ/G2L SoC family and the RZ/G3S SoC, which use the ravb driver. Along
>>>> the way, we do some refactoring and ensure that napi_complete_done() is
>>>> used in accordance with the NAPI documentation for both GbEth and R-Car
>>>> code paths.
>>>>
>>>> Performance improvment mainly comes from enabling SW IRQ Coalescing for
>>>
>>>    And in "improvment" too... :-/
>>
>> I'll fix this and the above type in v3.
> 
>    TIA! Chances are this will end up in the merge commit...
> 
>>>> all SoCs using the GbEth IP, and NAPI Threaded mode for single core SoCs
>>>> using the GbEth IP. These can be enabled/disabled at runtime via sysfs,
>>>> but our goal is to set sensible defaults which get good performance on
>>>> the affected SoCs.
>>>>
>>>> The performance impact of this series on iperf3 testing is as follows:
>>>>   * RZ/G2L Ethernet throughput is unchanged, but CPU usage drops:
>>>>       * Bidirectional and TCP RX: 6.5% less CPU usage
>>>>       * UDP RX: 10% less CPU usage
>>>>
>>>>   * RZ/G2UL and RZ/G3S Ethernet throughput is increased for all test
>>>>     cases except UDP TX, which suffers a slight loss:
>>>>       * TCP TX: 32% more throughput
>>>>       * TCP RX: 11% more throughput
>>>>       * UDP TX: 10% less throughput
>>>>       * UDP RX: 10183% more throughput - the previous throughput of
>>>
>>>    So this is a real figure? I thought you forgot to erase 10... :-)
>>
>> Yes, throughput went from 1.06Mbps to 109Mbps for the RZ/G2UL with these
>> changes.
> 
>    Hm, that gives me even 10283%! :-)

   Stupid me, forgot to subtract 100%... :-)

[...]

MBR, Sergey