netdev - Re: [PATCH v2 net-next 2/3] net: mvmdio: Avoid excessive sleeps in polled mode

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Message-ID: <2c385c4b-def5-4f43-a35c-68152107f19c@lunn.ch>
Date: Tue, 5 Dec 2023 16:11:59 +0100
From: Andrew Lunn <andrew@...n.ch>
To: Tobias Waldekranz <tobias@...dekranz.com>
Cc: davem@...emloft.net, kuba@...nel.org, gregory.clement@...tlin.com,
	sebastian.hesselbarth@...il.com, robh+dt@...nel.org,
	krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
	netdev@...r.kernel.org
Subject: Re: [PATCH v2 net-next 2/3] net: mvmdio: Avoid excessive sleeps in
 polled mode

On Mon, Dec 04, 2023 at 11:08:10AM +0100, Tobias Waldekranz wrote:
> Before this change, when operating in polled mode, i.e. no IRQ is
> available, every individual C45 access would be hit with a 150us sleep
> after the bus access.
> 
> For example, on a board with a CN9130 SoC connected to an MV88X3310
> PHY, a single C45 read would take around 165us:
> 
>     root@...ix:~$ mdio f212a600.mdio-mii mmd 4:1 bench 0xc003
>     Performed 1000 reads in 165ms
> 
> By replacing the long sleep with a tighter poll loop, we observe a 10x
> increase in bus throughput:
> 
>     root@...ix:~$ mdio f212a600.mdio-mii mmd 4:1 bench 0xc003
>     Performed 1000 reads in 15ms
> 
> Signed-off-by: Tobias Waldekranz <tobias@...dekranz.com>

Reviewed-by: Andrew Lunn <andrew@...n.ch>

    Andrew