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From: "Rafał Miłecki" <zajec5@gmail.com>
To: Russell King - ARM Linux admin <linux@armlinux.org.uk>
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 13:16:12 +0200	[thread overview]
Message-ID: <CACna6ryVxFr8ho3ekY4Q_J=TamVLv9ZMDaHJFUGcEGSRrSVaHA@mail.gmail.com> (raw)
In-Reply-To: <20190521104512.2r67fydrgniwqaja@shell.armlinux.org.uk>

On Tue, 21 May 2019 at 12:45, Russell King - ARM Linux admin
<linux@armlinux.org.uk> wrote:
> On Tue, May 21, 2019 at 12:28:48PM +0200, Rafał Miłecki wrote:
> > 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.

That was my guess as well, that's why I tried "cachestat" tool.


> You could try aligning some of the cache flushing code to a cache line
> and see what effect that has.

Can you give me some extra hint on how to do that, please? I tried
searching for it a bit but I didn't find any clear article on that
matter.

-- 
Rafał

  reply	other threads:[~2019-05-21 11:16 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
2019-05-21 11:16   ` Rafał Miłecki [this message]
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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