netdev - Re: [PATCH net-next v4 0/4] Add support to do threaded napi busy poll

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Message-ID: <CAAywjhSc6+wTKs3cSmB0hvvPSKxK0=pd-8FbCivnLr3bYgFNnA@mail.gmail.com>
Date: Thu, 27 Mar 2025 12:35:29 -0700
From: Samiullah Khawaja <skhawaja@...gle.com>
To: Joe Damato <jdamato@...tly.com>, Stanislav Fomichev <stfomichev@...il.com>, 
	Samiullah Khawaja <skhawaja@...gle.com>, Martin Karsten <mkarsten@...terloo.ca>, 
	Jakub Kicinski <kuba@...nel.org>, "David S . Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>, almasrymina@...gle.com, 
	willemb@...gle.com, netdev@...r.kernel.org
Subject: Re: [PATCH net-next v4 0/4] Add support to do threaded napi busy poll

On Thu, Mar 27, 2025 at 11:40 AM Joe Damato <jdamato@...tly.com> wrote:
>
> On Wed, Mar 26, 2025 at 02:57:37PM -0700, Stanislav Fomichev wrote:
> > On 03/26, Samiullah Khawaja wrote:
> > > On Tue, Mar 25, 2025 at 10:47 AM Martin Karsten <mkarsten@...terloo.ca> wrote:
> > > >
> > > > On 2025-03-25 12:40, Samiullah Khawaja wrote:
> > > > > On Sun, Mar 23, 2025 at 7:38 PM Martin Karsten <mkarsten@...terloo.ca> wrote:
> > > > >>
> > > > >> On 2025-03-20 22:15, Samiullah Khawaja wrote:
>
> > > > > Nice catch. It seems a recent change broke the busy polling for AF_XDP
> > > > > and there was a fix for the XDP_ZEROCOPY but the XDP_COPY remained
> > > > > broken and seems in my experiments I didn't pick that up. During my
> > > > > experimentation I confirmed that all experiment modes are invoking the
> > > > > busypoll and not going through softirqs. I confirmed this through perf
> > > > > traces. I sent out a fix for XDP_COPY busy polling here in the link
> > > > > below. I will resent this for the net since the original commit has
> > > > > already landed in 6.13.
> > > > > https://lore.kernel.org/netdev/CAAywjhSEjaSgt7fCoiqJiMufGOi=oxa164_vTfk+3P43H60qwQ@mail.gmail.com/T/#t
> >
> > In general, when sending the patches and numbers, try running everything
> > against the latest net-next. Otherwise, it is very confusing to reason
> > about..
>
> I had mentioned in my previous review, but worth mentioning again...
> using --base=auto when using format-patch to generate the base
> commit SHA would be really useful to potentially help avoid this
> problem.
I completely agree. But I have 2 platforms that I am working with,
virito-net and idpf. I use idpf to generate experiment data but I
cannot use the latest kernel with it since the AF_XDP support for it
is broken. And I generate patches using format-patch after rebasing on
top of net-next and doing functional testing with qemu. This is to
make sure that the patches don't have any conflicts with the latest
net-next.