From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: "Samudrala\, Sridhar" <sridhar.samudrala@intel.com>,
magnus.karlsson@intel.com, bjorn.topel@intel.com,
netdev@vger.kernel.org, bpf@vger.kernel.org,
intel-wired-lan@lists.osuosl.org, maciej.fijalkowski@intel.com,
tom.herbert@intel.com
Subject: Re: [PATCH bpf-next 0/5] Add support for SKIP_BPF flag for AF_XDP sockets
Date: Thu, 15 Aug 2019 19:11:11 +0200 [thread overview]
Message-ID: <87ftm2wdzk.fsf@toke.dk> (raw)
In-Reply-To: <b9423054-247e-8b57-ea59-42368f60ea1e@intel.com>
"Samudrala, Sridhar" <sridhar.samudrala@intel.com> writes:
> On 8/15/2019 4:12 AM, Toke Høiland-Jørgensen wrote:
>> Sridhar Samudrala <sridhar.samudrala@intel.com> writes:
>>
>>> This patch series introduces XDP_SKIP_BPF flag that can be specified
>>> during the bind() call of an AF_XDP socket to skip calling the BPF
>>> program in the receive path and pass the buffer directly to the socket.
>>>
>>> When a single AF_XDP socket is associated with a queue and a HW
>>> filter is used to redirect the packets and the app is interested in
>>> receiving all the packets on that queue, we don't need an additional
>>> BPF program to do further filtering or lookup/redirect to a socket.
>>>
>>> Here are some performance numbers collected on
>>> - 2 socket 28 core Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz
>>> - Intel 40Gb Ethernet NIC (i40e)
>>>
>>> All tests use 2 cores and the results are in Mpps.
>>>
>>> turbo on (default)
>>> ---------------------------------------------
>>> no-skip-bpf skip-bpf
>>> ---------------------------------------------
>>> rxdrop zerocopy 21.9 38.5
>>> l2fwd zerocopy 17.0 20.5
>>> rxdrop copy 11.1 13.3
>>> l2fwd copy 1.9 2.0
>>>
>>> no turbo : echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo
>>> ---------------------------------------------
>>> no-skip-bpf skip-bpf
>>> ---------------------------------------------
>>> rxdrop zerocopy 15.4 29.0
>>> l2fwd zerocopy 11.8 18.2
>>> rxdrop copy 8.2 10.5
>>> l2fwd copy 1.7 1.7
>>> ---------------------------------------------
>>
>> You're getting this performance boost by adding more code in the fast
>> path for every XDP program; so what's the performance impact of that for
>> cases where we do run an eBPF program?
>
> The no-skip-bpf results are pretty close to what i see before the
> patches are applied. As umem is cached in rx_ring for zerocopy the
> overhead is much smaller compared to the copy scenario where i am
> currently calling xdp_get_umem_from_qid().
I meant more for other XDP programs; what is the performance impact of
XDP_DROP, for instance?
>> Also, this is basically a special-casing of a particular deployment
>> scenario. Without a way to control RX queue assignment and traffic
>> steering, you're basically hard-coding a particular app's takeover of
>> the network interface; I'm not sure that is such a good idea...
>
> Yes. This is mainly targeted for application that create 1 AF_XDP
> socket per RX queue and can use a HW filter (via ethtool or TC flower)
> to redirect the packets to a queue or a group of queues.
Yeah, and I'd prefer it if the handling of this to be unified somehow...
-Toke
next prev parent reply other threads:[~2019-08-15 17:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-15 3:46 [PATCH bpf-next 0/5] Add support for SKIP_BPF flag for AF_XDP sockets Sridhar Samudrala
2019-08-15 3:46 ` [PATCH bpf-next 1/5] xsk: Convert bool 'zc' field in struct xdp_umem to a u32 bitmap Sridhar Samudrala
2019-08-15 3:46 ` [PATCH bpf-next 2/5] xsk: Introduce XDP_SKIP_BPF bind option Sridhar Samudrala
2019-08-15 3:46 ` [PATCH bpf-next 3/5] i40e: Enable XDP_SKIP_BPF option for AF_XDP sockets Sridhar Samudrala
2019-08-16 9:21 ` kbuild test robot
2019-08-15 3:46 ` [PATCH bpf-next 4/5] ixgbe: " Sridhar Samudrala
2019-08-15 3:46 ` [PATCH bpf-next 5/5] xdpsock_user: Add skip_bpf option Sridhar Samudrala
2019-08-15 11:12 ` [PATCH bpf-next 0/5] Add support for SKIP_BPF flag for AF_XDP sockets Toke Høiland-Jørgensen
2019-08-15 16:25 ` Samudrala, Sridhar
2019-08-15 17:11 ` Toke Høiland-Jørgensen [this message]
2019-08-16 6:12 ` Samudrala, Sridhar
2019-08-15 12:51 ` Björn Töpel
2019-08-15 16:46 ` Samudrala, Sridhar
2019-08-16 13:32 ` [Intel-wired-lan] " Björn Töpel
2019-08-16 22:08 ` Jonathan Lemon
2019-08-19 7:39 ` Björn Töpel
2019-08-15 19:28 ` Jakub Kicinski
2019-08-16 6:25 ` Samudrala, Sridhar
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