netdev - Re: [PATCH net] r8169: fix NAPI handling under high load

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Message-ID: <20181018061554.GF2487@marvin.atrad.com.au>
Date:   Thu, 18 Oct 2018 16:45:54 +1030
From:   Jonathan Woithe <jwoithe@...ad.com.au>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     Francois Romieu <romieu@...zoreil.com>,
        Holger Hoffstätte 
        <holger@...lied-asynchrony.com>,
        David Miller <davem@...emloft.net>,
        Realtek linux nic maintainers <nic_swsd@...ltek.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH net] r8169: fix NAPI handling under high load

On Thu, Oct 18, 2018 at 08:03:32AM +0200, Heiner Kallweit wrote:
> On 18.10.2018 07:58, Jonathan Woithe wrote:
> > On Thu, Oct 18, 2018 at 01:30:51AM +0200, Francois Romieu wrote:
> >> Holger Hoffstätte <holger@...lied-asynchrony.com> :
> >> [...]
> >> The bug will induce delayed rx processing when a spike of "load" is
> >> followed by an idle period.
> > 
> > If this is the case, I wonder whether this bug might also be the cause of
> > the long reception delays we've observed at times when a period of high
> > network load is followed by almost nothing[1].  That thread[2] details the
> > investigations subsequently done.  A git bisect showed that commit
> > da78dbff2e05630921c551dbbc70a4b7981a8fff was the origin of the misbehaviour
> > we were observing.
> > 
> > We still see the problem when we test with recent kernels.  It would be
> > great if the underlying problem has now been identified.
> > 
> > I can possibly scrape some hardware together to test any proposed fix under
> > our workload if there was interest.
> > 
> Proposed fix is here:
> https://patchwork.ozlabs.org/patch/985014/
> Would be good if you could test it. Thanks!

I should be able to do so tomorrow.  Which kernel would you like me to apply
the patch to?

Regards
  jonathan