RE: [PATCH RESEND v11 2/4] xdp: extend xdp_redirect_map with broadcast support

[John Fastabend <john.fastabend@gmail.com>]

Hangbin Liu wrote:
> This patch adds two flags BPF_F_BROADCAST and BPF_F_EXCLUDE_INGRESS to
> extend xdp_redirect_map for broadcast support.
> 
> With BPF_F_BROADCAST the packet will be broadcasted to all the interfaces
> in the map. with BPF_F_EXCLUDE_INGRESS the ingress interface will be
> excluded when do broadcasting.
> 
> When getting the devices in dev hash map via dev_map_hash_get_next_key(),
> there is a possibility that we fall back to the first key when a device
> was removed. This will duplicate packets on some interfaces. So just walk
> the whole buckets to avoid this issue. For dev array map, we also walk the
> whole map to find valid interfaces.
> 
> Function bpf_clear_redirect_map() was removed in
> commit ee75aef23afe ("bpf, xdp: Restructure redirect actions").
> Add it back as we need to use ri->map again.
> 
> With test topology:
>   +-------------------+             +-------------------+
>   | Host A (i40e 10G) |  ---------- | eno1(i40e 10G)    |
>   +-------------------+             |                   |
>                                     |   Host B          |
>   +-------------------+             |                   |
>   | Host C (i40e 10G) |  ---------- | eno2(i40e 10G)    |
>   +-------------------+             |                   |
>                                     |          +------+ |
>                                     | veth0 -- | Peer | |
>                                     | veth1 -- |      | |
>                                     | veth2 -- |  NS  | |
>                                     |          +------+ |
>                                     +-------------------+
> 
> On Host A:
>  # pktgen/pktgen_sample03_burst_single_flow.sh -i eno1 -d $dst_ip -m $dst_mac -s 64
> 
> On Host B(Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz, 128G Memory):
> Use xdp_redirect_map and xdp_redirect_map_multi in samples/bpf for testing.
> All the veth peers in the NS have a XDP_DROP program loaded. The
> forward_map max_entries in xdp_redirect_map_multi is modify to 4.
> 
> Testing the performance impact on the regular xdp_redirect path with and
> without patch (to check impact of additional check for broadcast mode):
> 
> 5.12 rc4         | redirect_map        i40e->i40e      |    2.0M |  9.7M
> 5.12 rc4         | redirect_map        i40e->veth      |    1.7M | 11.8M
> 5.12 rc4 + patch | redirect_map        i40e->i40e      |    2.0M |  9.6M
> 5.12 rc4 + patch | redirect_map        i40e->veth      |    1.7M | 11.7M
> 
> Testing the performance when cloning packets with the redirect_map_multi
> test, using a redirect map size of 4, filled with 1-3 devices:
> 
> 5.12 rc4 + patch | redirect_map multi  i40e->veth (x1) |    1.7M | 11.4M
> 5.12 rc4 + patch | redirect_map multi  i40e->veth (x2) |    1.1M |  4.3M
> 5.12 rc4 + patch | redirect_map multi  i40e->veth (x3) |    0.8M |  2.6M
> 
> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
> Acked-by: Martin KaFai Lau <kafai@fb.com>
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>

[...]

LGTM thanks for sticking with it.

Acked-by: John Fastabend <john.fastabend@gmail.com>