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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Stanislav Fomichev <sdf@google.com>
Cc: Network Development <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Song Liu <songliubraving@fb.com>,
	Willem de Bruijn <willemb@google.com>,
	Petar Penkov <ppenkov@google.com>
Subject: Re: [PATCH bpf-next v3 0/7] bpf/flow_dissector: support input flags
Date: Thu, 25 Jul 2019 18:06:03 -0700	[thread overview]
Message-ID: <CAADnVQJDcWQp9ZJ5GTaKez3FjAUTPUPHWuJ7-dnnb9qm88He+w@mail.gmail.com> (raw)
In-Reply-To: <20190725225231.195090-1-sdf@google.com>

On Thu, Jul 25, 2019 at 3:52 PM Stanislav Fomichev <sdf@google.com> wrote:
>
> C flow dissector supports input flags that tell it to customize parsing
> by either stopping early or trying to parse as deep as possible.
> BPF flow dissector always parses as deep as possible which is sub-optimal.
> Pass input flags to the BPF flow dissector as well so it can make the same
> decisions.
>
> Series outline:
> * remove unused FLOW_DISSECTOR_F_STOP_AT_L3 flag
> * export FLOW_DISSECTOR_F_XXX flags as uapi and pass them to BPF
>   flow dissector
> * add documentation for the export flags
> * support input flags in BPF_PROG_TEST_RUN via ctx_{in,out}
> * sync uapi to tools
> * support FLOW_DISSECTOR_F_PARSE_1ST_FRAG in selftest
> * support FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL in kernel and selftest
> * support FLOW_DISSECTOR_F_STOP_AT_ENCAP in selftest
>
> Pros:
> * makes BPF flow dissector faster by avoiding burning extra cycles
> * existing BPF progs continue to work by ignoring the flags and always
>   parsing as deep as possible
>
> Cons:
> * new UAPI which we need to support (OTOH, if we need to deprecate some
>   flags, we can just stop setting them upon calling BPF programs)
>
> Some numbers (with .repeat = 4000000 in test_flow_dissector):
>         test_flow_dissector:PASS:ipv4-frag 35 nsec
>         test_flow_dissector:PASS:ipv4-frag 35 nsec
>         test_flow_dissector:PASS:ipv4-no-frag 32 nsec
>         test_flow_dissector:PASS:ipv4-no-frag 32 nsec
>
>         test_flow_dissector:PASS:ipv6-frag 39 nsec
>         test_flow_dissector:PASS:ipv6-frag 39 nsec
>         test_flow_dissector:PASS:ipv6-no-frag 36 nsec
>         test_flow_dissector:PASS:ipv6-no-frag 36 nsec
>
>         test_flow_dissector:PASS:ipv6-flow-label 36 nsec
>         test_flow_dissector:PASS:ipv6-flow-label 36 nsec
>         test_flow_dissector:PASS:ipv6-no-flow-label 33 nsec
>         test_flow_dissector:PASS:ipv6-no-flow-label 33 nsec
>
>         test_flow_dissector:PASS:ipip-encap 38 nsec
>         test_flow_dissector:PASS:ipip-encap 38 nsec
>         test_flow_dissector:PASS:ipip-no-encap 32 nsec
>         test_flow_dissector:PASS:ipip-no-encap 32 nsec
>
> The improvement is around 10%, but it's in a tight cache-hot
> BPF_PROG_TEST_RUN loop.

Applied. Thanks

      parent reply	other threads:[~2019-07-26  1:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-25 22:52 [PATCH bpf-next v3 0/7] bpf/flow_dissector: support input flags Stanislav Fomichev
2019-07-25 22:52 ` [PATCH bpf-next v3 1/7] bpf/flow_dissector: pass input flags to BPF flow dissector program Stanislav Fomichev
2019-07-25 22:52 ` [PATCH bpf-next v3 2/7] bpf/flow_dissector: document flags Stanislav Fomichev
2019-07-25 22:52 ` [PATCH bpf-next v3 3/7] bpf/flow_dissector: support flags in BPF_PROG_TEST_RUN Stanislav Fomichev
2019-07-25 22:52 ` [PATCH bpf-next v3 4/7] tools/bpf: sync bpf_flow_keys flags Stanislav Fomichev
2019-07-25 22:52 ` [PATCH bpf-next v3 5/7] selftests/bpf: support BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG Stanislav Fomichev
2019-07-25 22:52 ` [PATCH bpf-next v3 6/7] bpf/flow_dissector: support ipv6 flow_label and BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL Stanislav Fomichev
2019-07-25 22:52 ` [PATCH bpf-next v3 7/7] selftests/bpf: support BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP Stanislav Fomichev
2019-08-27 18:04   ` Eric Dumazet
2019-08-27 18:19     ` Stanislav Fomichev
2019-07-26  1:06 ` Alexei Starovoitov [this message]

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