From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Subject: Re: [RFC PATCH v2 1/5] bpf: add PHYS_DEV prog type for early driver
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Date: Sat, 9 Apr 2016 10:26:37 -0700
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Cc: Tom Herbert <tom@herbertland.com>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Brenden Blanco <bblanco@plumgrid.com>,
	"David S. Miller" <davem@davemloft.net>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>,
	Or Gerlitz <ogerlitz@mellanox.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Edward Cree <ecree@solarflare.com>,
	john fastabend <john.fastabend@gmail.com>,
	Thomas Graf <tgraf@suug.ch>,
	Johannes Berg <johannes@sipsolutions.net>,
	eranlinuxmellanox@gmail.com, Lorenzo Colitti <lorenzo@google.com>,
	linux-mm <linux-mm@kvack.org>
To: Jamal Hadi Salim <jhs@mojatatu.com>
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On Sat, Apr 09, 2016 at 11:29:18AM -0400, Jamal Hadi Salim wrote:
> On 16-04-09 07:29 AM, Tom Herbert wrote:
> 
> >+1. Forwarding which will be a common application almost always
> >requires modification (decrement TTL), and header data split has
> >always been a weak feature since the device has to have some arbitrary
> >rules about what headers needs to be split out (either implements
> >protocol specific parsing or some fixed length).
> 
> Then this is sensible. I was cruising the threads and
> confused by your earlier emails Tom because you talked
> about XPS etc. It sounded like the idea evolved into putting
> the whole freaking stack on bpf.

yeah, no stack, no queues in bpf.

> If this is _forwarding only_ it maybe useful to look at
> Alexey's old code in particular the DMA bits;
> he built his own lookup algorithm but sounds like bpf is
> a much better fit today.

a link to these old bits?

Just to be clear: this rfc is not the only thing we're considering.
In particular huawei guys did a monster effort to improve performance
in this area as well. We'll try to blend all the code together and
pick what's the best.

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