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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>
Cc: "Network Development" <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"David Miller" <davem@davemloft.net>,
	"Jesper Dangaard Brouer" <brouer@redhat.com>,
	"Björn Töpel" <bjorn.topel@gmail.com>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Maciej Fijalkowski" <maciej.fijalkowski@intel.com>
Subject: Re: [PATCH bpf-next v3 0/3] xdp: Introduce bulking for non-map XDP_REDIRECT
Date: Thu, 16 Jan 2020 20:06:55 -0800
Message-ID: <CAADnVQJNJ4G2NGGAOe-khAgT2UUE3WxcP2FgT-4Ep9G0afpVfA@mail.gmail.com> (raw)
In-Reply-To: <157918768284.1458396.8128704597152008763.stgit@toke.dk>

On Thu, Jan 16, 2020 at 7:14 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
> Since commit 96360004b862 ("xdp: Make devmap flush_list common for all map
> instances"), devmap flushing is a global operation instead of tied to a
> particular map. This means that with a bit of refactoring, we can finally fix
> the performance delta between the bpf_redirect_map() and bpf_redirect() helper
> functions, by introducing bulking for the latter as well.
> This series makes this change by moving the data structure used for the bulking
> into struct net_device itself, so we can access it even when there is not
> devmap. Once this is done, moving the bpf_redirect() helper to use the bulking
> mechanism becomes quite trivial, and brings bpf_redirect() up to the same as
> bpf_redirect_map():
>                        Before:   After:
> 1 CPU:
> bpf_redirect_map:      8.4 Mpps  8.4 Mpps  (no change)
> bpf_redirect:          5.0 Mpps  8.4 Mpps  (+68%)
> 2 CPUs:
> bpf_redirect_map:     15.9 Mpps  16.1 Mpps  (+1% or ~no change)
> bpf_redirect:          9.5 Mpps  15.9 Mpps  (+67%)
> After this patch series, the only semantics different between the two variants
> of the bpf() helper (apart from the absence of a map argument, obviously) is
> that the _map() variant will return an error if passed an invalid map index,
> whereas the bpf_redirect() helper will succeed, but drop packets on
> xdp_do_redirect(). This is because the helper has no reference to the calling
> netdev, so unfortunately we can't do the ifindex lookup directly in the helper.
> Changelog:
> v3:
>   - Switch two more fields to avoid a list_head spanning two cache lines
>   - Include Jesper's tracepoint patch
>   - Also rename xdp_do_flush_map()
>   - Fix a few nits from Maciej

Applied. Thanks

      parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16 15:14 Toke Høiland-Jørgensen
2020-01-16 15:14 ` [PATCH bpf-next v3 1/3] xdp: Move devmap bulk queue into struct net_device Toke Høiland-Jørgensen
2020-01-16 15:14 ` [PATCH bpf-next v3 2/3] xdp: Use bulking for non-map XDP_REDIRECT and consolidate code paths Toke Høiland-Jørgensen
2020-01-16 15:14 ` [PATCH bpf-next v3 3/3] devmap: Adjust tracepoint for map-less queue flush Toke Høiland-Jørgensen
2020-01-17  4:06 ` Alexei Starovoitov [this message]

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