From: Alexei Starovoitov <ast@fb.com>
To: Eric Dumazet <eric.dumazet@gmail.com>, Martin KaFai Lau <kafai@fb.com>
Cc: <netdev@vger.kernel.org>, Brenden Blanco <bblanco@plumgrid.com>,
"Daniel Borkmann" <daniel@iogearbox.net>,
David Miller <davem@davemloft.net>,
"Saeed Mahameed" <saeedm@mellanox.com>,
Tariq Toukan <tariqt@mellanox.com>,
"Kernel Team" <kernel-team@fb.com>
Subject: Re: [PATCH net-next 2/4] mlx4: xdp: Allow raising MTU up to one page minus eth and vlan hdrs
Date: Fri, 2 Dec 2016 16:53:09 -0800 [thread overview]
Message-ID: <58421775.6090905@fb.com> (raw)
In-Reply-To: <1480725480.18162.394.camel@edumazet-glaptop3.roam.corp.google.com>
On 12/2/16 4:38 PM, Eric Dumazet wrote:
> On Fri, 2016-12-02 at 15:23 -0800, Martin KaFai Lau wrote:
>> When XDP prog is attached, it is currently limiting
>> MTU to be FRAG_SZ0 - ETH_HLEN - (2 * VLAN_HLEN) which is 1514
>> in x86.
>>
>> AFAICT, since mlx4 is doing one page per packet for XDP,
>> we can at least raise the MTU limitation up to
>> PAGE_SIZE - ETH_HLEN - (2 * VLAN_HLEN) which this patch is
>> doing. It will be useful in the next patch which allows
>> XDP program to extend the packet by adding new header(s).
>>
>> Signed-off-by: Martin KaFai Lau <kafai@fb.com>
>> ---
>
> Have you tested your patch on a host with PAGE_SIZE = 64 KB ?
>
> Looks XDP really kills arches with bigger pages :(
I'm afraid xdp mlx[45] support was not tested on arches
with 64k pages at all. Not just this patch.
I think people who care about such archs should test?
Note page per packet is not a hard requirement for all drivers
and all archs. For mlx[45] it was the easiest and the most
convenient way to achieve desired performance.
If there are ways to do the same performance differently,
I'm all ears :)
next prev parent reply other threads:[~2016-12-03 0:53 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-02 23:23 [PATCH net-next 0/4]: Allow head adjustment in XDP prog Martin KaFai Lau
2016-12-02 23:23 ` [PATCH net-next 1/4] bpf: xdp: " Martin KaFai Lau
2016-12-03 0:22 ` Daniel Borkmann
2016-12-03 3:43 ` Martin KaFai Lau
2016-12-03 15:24 ` Jesper Dangaard Brouer
2016-12-03 19:32 ` Martin KaFai Lau
2016-12-03 20:21 ` Daniel Borkmann
2016-12-02 23:23 ` [PATCH net-next 2/4] mlx4: xdp: Allow raising MTU up to one page minus eth and vlan hdrs Martin KaFai Lau
2016-12-03 0:07 ` Rick Jones
2016-12-04 3:19 ` Martin KaFai Lau
2016-12-05 17:46 ` Jakub Kicinski
2016-12-03 0:38 ` Eric Dumazet
2016-12-03 0:53 ` Alexei Starovoitov [this message]
2016-12-03 2:15 ` Eric Dumazet
2016-12-03 3:42 ` Martin KaFai Lau
2016-12-03 3:59 ` Eric Dumazet
2016-12-04 23:31 ` Saeed Mahameed
2016-12-05 0:52 ` Eric Dumazet
2016-12-02 23:23 ` [PATCH net-next 3/4] mlx4: xdp: Reserve headroom for receiving packet when XDP prog is active Martin KaFai Lau
2016-12-02 23:23 ` [PATCH net-next 4/4] bpf: xdp: Add XDP example for head adjustment Martin KaFai Lau
2016-12-03 15:17 ` [PATCH net-next 0/4]: Allow head adjustment in XDP prog Jesper Dangaard Brouer
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