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From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: "Rafał Miłecki" <zajec5@gmail.com>
Cc: Network Development <netdev@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-block@vger.kernel.org, John Crispin <john@phrozen.org>,
	Jonas Gorski <jonas.gorski@gmail.com>,
	Jo-Philipp Wich <jo@mein.io>, Felix Fietkau <nbd@nbd.name>
Subject: Re: ARM router NAT performance affected by random/unrelated commits
Date: Tue, 21 May 2019 11:45:12 +0100	[thread overview]
Message-ID: <20190521104512.2r67fydrgniwqaja@shell.armlinux.org.uk> (raw)
In-Reply-To: <9a9ba4c9-3cb7-eb64-4aac-d43b59224442@gmail.com>

On Tue, May 21, 2019 at 12:28:48PM +0200, Rafał Miłecki wrote:
> Hi,
> 
> I work on home routers based on Broadcom's Northstar SoCs. Those devices
> have ARM Cortex-A9 and most of them are dual-core.
> 
> As for home routers, my main concern is network performance. That CPU
> isn't powerful enough to handle gigabit traffic so all kind of
> optimizations do matter. I noticed some unexpected changes in NAT
> performance when switching between kernels.
> 
> My hardware is BCM47094 SoC (dual core ARM) with integrated network
> controller and external BCM53012 switch.

Guessing, I'd say it's to do with the placement of code wrt cachelines.
You could try aligning some of the cache flushing code to a cache line
and see what effect that has.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up

  reply	other threads:[~2019-05-21 10:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-21 10:28 Rafał Miłecki
2019-05-21 10:45 ` Russell King - ARM Linux admin [this message]
2019-05-21 11:16   ` Rafał Miłecki
2019-05-21 11:19     ` Russell King - ARM Linux admin
2019-05-22 11:51   ` Rafał Miłecki
2019-05-22 12:17     ` Russell King - ARM Linux admin
2019-05-22 21:12       ` Rafał Miłecki
2019-05-21 13:01 ` Andrew Lunn

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