From: Maryam Tahhan <mtahhan@redhat.com>
To: Magnus Karlsson <magnus.karlsson@gmail.com>,
Jesper Dangaard Brouer <jbrouer@redhat.com>
Cc: brouer@redhat.com, bpf@vger.kernel.org, netdev@vger.kernel.org,
xdp-hints@xdp-project.net, larysa.zaremba@intel.com,
memxor@gmail.com, Lorenzo Bianconi <lorenzo@kernel.org>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Daniel Borkmann <borkmann@iogearbox.net>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>,
dave@dtucker.co.uk, Magnus Karlsson <magnus.karlsson@intel.com>,
bjorn@kernel.org
Subject: Re: [PATCH RFCv2 bpf-next 17/18] xsk: AF_XDP xdp-hints support in desc options
Date: Fri, 9 Sep 2022 09:12:38 +0100 [thread overview]
Message-ID: <e1ab2141-03cc-f97c-3788-59923a029203@redhat.com> (raw)
In-Reply-To: <CAJ8uoz0CD18RUYU4SMsubB8fhv3uOwp6wi_uKsZSu_aOV5piaA@mail.gmail.com>
<snip>
>>>>
>>>> * Instead encode this information into each metadata entry in the
>>>> metadata area, in some way so that a flags field is not needed (-1
>>>> signifies not valid, or whatever happens to make sense). This has the
>>>> drawback that the user might have to look at a large number of entries
>>>> just to find out there is nothing valid to read. To alleviate this, it
>>>> could be combined with the next suggestion.
>>>>
>>>> * Dedicate one bit in the options field to indicate that there is at
>>>> least one valid metadata entry in the metadata area. This could be
>>>> combined with the two approaches above. However, depending on what
>>>> metadata you have enabled, this bit might be pointless. If some
>>>> metadata is always valid, then it serves no purpose. But it might if
>>>> all enabled metadata is rarely valid, e.g., if you get an Rx timestamp
>>>> on one packet out of one thousand.
>>>>
>>
>> I like this option better! Except that I have hoped to get 2 bits ;-)
>
> I will give you two if you need it Jesper, no problem :-).
>
Ok I will look at implementing and testing this and post an update.
Thanks folks
>> The performance advantage is that the AF_XDP descriptor bits will
>> already be cache-hot, and if it indicates no-metadata-hints the AF_XDP
>> application can avoid reading the metadata cache-line :-).
>
> Agreed. I prefer if we can keep it simple and fast like this.
>
<snip>
next prev parent reply other threads:[~2022-09-09 8:12 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-07 15:45 [PATCH RFCv2 bpf-next 00/18] XDP-hints: XDP gaining access to HW offload hints via BTF Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 01/18] libbpf: factor out BTF loading from load_module_btfs() Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 02/18] libbpf: try to load vmlinux BTF from the kernel first Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 03/18] libbpf: patch module BTF obj+type ID into BPF insns Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 04/18] net: create xdp_hints_common and set functions Jesper Dangaard Brouer
2022-09-09 10:49 ` Burakov, Anatoly
2022-09-09 14:13 ` [xdp-hints] " Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 05/18] net: add net_device feature flag for XDP-hints Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 06/18] xdp: controlling XDP-hints from BPF-prog via helper Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 07/18] i40e: Refactor i40e_ptp_rx_hwtstamp Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 08/18] i40e: refactor i40e_rx_checksum with helper Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 09/18] bpf: export btf functions for modules Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 10/18] btf: Add helper for kernel modules to lookup full BTF ID Jesper Dangaard Brouer
2022-09-07 15:45 ` [PATCH RFCv2 bpf-next 11/18] i40e: add XDP-hints handling Jesper Dangaard Brouer
2022-09-07 15:46 ` [PATCH RFCv2 bpf-next 12/18] net: use XDP-hints in xdp_frame to SKB conversion Jesper Dangaard Brouer
2022-09-07 15:46 ` [PATCH RFCv2 bpf-next 13/18] mvneta: add XDP-hints support Jesper Dangaard Brouer
2022-09-07 15:46 ` [PATCH RFCv2 bpf-next 14/18] i40e: Add xdp_hints_union Jesper Dangaard Brouer
2022-09-07 15:46 ` [PATCH RFCv2 bpf-next 15/18] ixgbe: enable xdp-hints Jesper Dangaard Brouer
2022-09-07 15:46 ` [PATCH RFCv2 bpf-next 16/18] ixgbe: add rx timestamp xdp hints support Jesper Dangaard Brouer
2022-09-07 15:46 ` [PATCH RFCv2 bpf-next 17/18] xsk: AF_XDP xdp-hints support in desc options Jesper Dangaard Brouer
2022-09-08 8:06 ` Magnus Karlsson
2022-09-08 10:10 ` Maryam Tahhan
2022-09-08 15:04 ` Jesper Dangaard Brouer
2022-09-09 6:43 ` Magnus Karlsson
2022-09-09 8:12 ` Maryam Tahhan [this message]
2022-09-09 9:42 ` Jesper Dangaard Brouer
2022-09-09 10:14 ` Magnus Karlsson
2022-09-09 12:35 ` [xdp-hints] " Jesper Dangaard Brouer
2022-09-09 12:44 ` Magnus Karlsson
2022-09-07 15:46 ` [PATCH RFCv2 bpf-next 18/18] ixgbe: AF_XDP xdp-hints processing in ixgbe_clean_rx_irq_zc Jesper Dangaard Brouer
2022-09-08 9:30 ` [xdp-hints] [PATCH RFCv2 bpf-next 00/18] XDP-hints: XDP gaining access to HW offload hints via BTF Alexander Lobakin
2022-09-09 13:48 ` Jesper Dangaard Brouer
2022-10-03 23:55 ` sdf
2022-10-04 9:29 ` Jesper Dangaard Brouer
2022-10-04 18:26 ` Stanislav Fomichev
2022-10-05 0:25 ` Martin KaFai Lau
2022-10-05 0:59 ` Jakub Kicinski
2022-10-05 1:02 ` Stanislav Fomichev
2022-10-05 1:24 ` Jakub Kicinski
2022-10-05 2:15 ` Stanislav Fomichev
2022-10-05 19:26 ` Martin KaFai Lau
2022-10-06 9:14 ` Magnus Karlsson
2022-10-06 15:29 ` Jesper Dangaard Brouer
2022-10-11 6:29 ` Martin KaFai Lau
2022-10-11 11:57 ` Jesper Dangaard Brouer
2022-10-05 10:06 ` [xdp-hints] " Toke Høiland-Jørgensen
2022-10-05 18:47 ` sdf
2022-10-06 8:19 ` Maryam Tahhan
2022-10-06 17:22 ` sdf
2022-10-05 14:19 ` Jesper Dangaard Brouer
2022-10-06 14:59 ` Jakub Kicinski
2022-10-05 13:43 ` Jesper Dangaard Brouer
2022-10-05 16:29 ` Jesper Dangaard Brouer
2022-10-05 18:43 ` sdf
2022-10-06 17:47 ` Jesper Dangaard Brouer
2022-10-07 15:05 ` [xdp-hints] " David Ahern
2022-10-05 13:14 ` Burakov, Anatoly
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