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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: "Samudrala, Sridhar" <sridhar.samudrala@intel.com>
Cc: "Björn Töpel" <bjorn.topel@gmail.com>,
	"Björn Töpel" <bjorn.topel@intel.com>, bpf <bpf@vger.kernel.org>,
	intel-wired-lan <intel-wired-lan@lists.osuosl.org>,
	"Jakub Kicinski" <jakub.kicinski@netronome.com>,
	"Fijalkowski, Maciej" <maciej.fijalkowski@intel.com>,
	"Karlsson, Magnus" <magnus.karlsson@intel.com>,
	"Network Development" <netdev@vger.kernel.org>,
	"Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Herbert, Tom" <tom.herbert@intel.com>
Subject: Re: [Intel-wired-lan] FW: [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue
Date: Thu, 31 Oct 2019 16:15:34 -0700	[thread overview]
Message-ID: <CAADnVQLJ95j5jfh5jFApjs4bYzOxuPcrMgH9jbdGGvOWQEPRyQ@mail.gmail.com> (raw)
In-Reply-To: <2e27b8d9-4615-cd8d-93de-2adb75d8effa@intel.com>

On Thu, Oct 31, 2019 at 3:38 PM Samudrala, Sridhar
<sridhar.samudrala@intel.com> wrote:
>
> Alexei, Jakub
>
> Do you think it will be possible to avoid this overhead when mitigations are turned ON?

yes

> The other part of the overhead is going through the redirect path.
>
> Can i assume that your silence as an indication that you are now okay with optional bypass
> flag as long as it doesn't effect the normal XDP datapath. If so, i will respin and submit
> the patches against the latest bpf-next

I'm still against it.
Looks like the only motivation for it is extra overhead due to retpolines.
imo it's not a good reason to introduce a bunch of extra code helping
single kernel feature.
We will have proper solution for indirect calls.

WARNING: multiple messages have this Message-ID (diff)
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: intel-wired-lan@osuosl.org
Subject: [Intel-wired-lan] FW: [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue
Date: Thu, 31 Oct 2019 16:15:34 -0700	[thread overview]
Message-ID: <CAADnVQLJ95j5jfh5jFApjs4bYzOxuPcrMgH9jbdGGvOWQEPRyQ@mail.gmail.com> (raw)
In-Reply-To: <2e27b8d9-4615-cd8d-93de-2adb75d8effa@intel.com>

On Thu, Oct 31, 2019 at 3:38 PM Samudrala, Sridhar
<sridhar.samudrala@intel.com> wrote:
>
> Alexei, Jakub
>
> Do you think it will be possible to avoid this overhead when mitigations are turned ON?

yes

> The other part of the overhead is going through the redirect path.
>
> Can i assume that your silence as an indication that you are now okay with optional bypass
> flag as long as it doesn't effect the normal XDP datapath. If so, i will respin and submit
> the patches against the latest bpf-next

I'm still against it.
Looks like the only motivation for it is extra overhead due to retpolines.
imo it's not a good reason to introduce a bunch of extra code helping
single kernel feature.
We will have proper solution for indirect calls.

  reply	other threads:[~2019-10-31 23:15 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-08  6:16 [PATCH bpf-next 0/4] Enable direct receive on AF_XDP sockets Sridhar Samudrala
2019-10-08  6:16 ` [Intel-wired-lan] " Sridhar Samudrala
2019-10-08  6:16 ` [PATCH bpf-next 1/4] bpf: introduce bpf_get_prog_id and bpf_set_prog_id helper functions Sridhar Samudrala
2019-10-08  6:16   ` [Intel-wired-lan] " Sridhar Samudrala
2019-10-08  6:16 ` [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue Sridhar Samudrala
2019-10-08  6:16   ` [Intel-wired-lan] " Sridhar Samudrala
2019-10-08  6:58   ` Toke Høiland-Jørgensen
2019-10-08  6:58     ` [Intel-wired-lan] " Toke =?unknown-8bit?q?H=C3=B8iland-J=C3=B8rgensen?=
2019-10-08  8:47     ` Björn Töpel
2019-10-08  8:47       ` [Intel-wired-lan] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-08  8:48       ` Björn Töpel
2019-10-08  8:48         ` [Intel-wired-lan] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-08  9:04       ` Toke Høiland-Jørgensen
2019-10-08  9:04         ` [Intel-wired-lan] " Toke =?unknown-8bit?q?H=C3=B8iland-J=C3=B8rgensen?=
2019-10-08  8:05   ` Björn Töpel
2019-10-08  8:05     ` [Intel-wired-lan] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-09 16:32     ` Samudrala, Sridhar
2019-10-09 16:32       ` [Intel-wired-lan] " Samudrala, Sridhar
2019-10-09  1:20   ` Alexei Starovoitov
2019-10-09  1:20     ` [Intel-wired-lan] " Alexei Starovoitov
     [not found]     ` <3ED8E928C4210A4289A677D2FEB48235140134CE@fmsmsx111.amr.corp.intel.com>
2019-10-09 16:53       ` FW: " Samudrala, Sridhar
2019-10-09 16:53         ` [Intel-wired-lan] " Samudrala, Sridhar
2019-10-09 17:17         ` Alexei Starovoitov
2019-10-09 17:17           ` [Intel-wired-lan] " Alexei Starovoitov
2019-10-09 19:12           ` Samudrala, Sridhar
2019-10-09 19:12             ` [Intel-wired-lan] " Samudrala, Sridhar
2019-10-10  1:06             ` Alexei Starovoitov
2019-10-10  1:06               ` [Intel-wired-lan] " Alexei Starovoitov
2019-10-18 18:40               ` Samudrala, Sridhar
2019-10-18 18:40                 ` [Intel-wired-lan] " Samudrala, Sridhar
2019-10-18 19:22                 ` Toke Høiland-Jørgensen
2019-10-18 19:22                   ` [Intel-wired-lan] " Toke =?unknown-8bit?q?H=C3=B8iland-J=C3=B8rgensen?=
2019-10-19  0:14                 ` Alexei Starovoitov
2019-10-19  0:14                   ` [Intel-wired-lan] " Alexei Starovoitov
2019-10-19  0:45                   ` Samudrala, Sridhar
2019-10-19  0:45                     ` [Intel-wired-lan] " Samudrala, Sridhar
2019-10-19  2:25                     ` Alexei Starovoitov
2019-10-19  2:25                       ` [Intel-wired-lan] " Alexei Starovoitov
2019-10-20 10:14                       ` Toke Høiland-Jørgensen
2019-10-20 10:14                         ` [Intel-wired-lan] " Toke =?unknown-8bit?q?H=C3=B8iland-J=C3=B8rgensen?=
2019-10-20 17:12                         ` Björn Töpel
2019-10-20 17:12                           ` =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-21 20:10                           ` Samudrala, Sridhar
2019-10-21 20:10                             ` Samudrala, Sridhar
2019-10-21 22:34                             ` Alexei Starovoitov
2019-10-21 22:34                               ` Alexei Starovoitov
2019-10-22 19:06                               ` Samudrala, Sridhar
2019-10-22 19:06                                 ` Samudrala, Sridhar
2019-10-23 17:42                                 ` Alexei Starovoitov
2019-10-23 17:42                                   ` Alexei Starovoitov
2019-10-24 18:12                                   ` Samudrala, Sridhar
2019-10-24 18:12                                     ` Samudrala, Sridhar
2019-10-25  7:42                                     ` Björn Töpel
2019-10-25  7:42                                       ` =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-31 22:38                                       ` Samudrala, Sridhar
2019-10-31 22:38                                         ` Samudrala, Sridhar
2019-10-31 23:15                                         ` Alexei Starovoitov [this message]
2019-10-31 23:15                                           ` Alexei Starovoitov
2019-11-01  0:21                                         ` Jakub Kicinski
2019-11-01  0:21                                           ` Jakub Kicinski
2019-11-01 18:31                                           ` Samudrala, Sridhar
2019-11-01 18:31                                             ` Samudrala, Sridhar
2019-11-04  2:08                                           ` dan
2019-11-04  2:08                                             ` dan
2019-10-25  9:07                                   ` Björn Töpel
2019-10-25  9:07                                     ` =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-08  6:16 ` [PATCH bpf-next 3/4] libbpf: handle AF_XDP sockets created with XDP_DIRECT bind flag Sridhar Samudrala
2019-10-08  6:16   ` [Intel-wired-lan] " Sridhar Samudrala
2019-10-08  8:05   ` Björn Töpel
2019-10-08  8:05     ` [Intel-wired-lan] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-08  6:16 ` [PATCH bpf-next 4/4] xdpsock: add an option to create AF_XDP sockets in XDP_DIRECT mode Sridhar Samudrala
2019-10-08  6:16   ` [Intel-wired-lan] " Sridhar Samudrala
2019-10-08  8:05   ` Björn Töpel
2019-10-08  8:05     ` [Intel-wired-lan] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-08  8:05 ` [PATCH bpf-next 0/4] Enable direct receive on AF_XDP sockets Björn Töpel
2019-10-08  8:05   ` [Intel-wired-lan] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-10-09 16:19   ` Samudrala, Sridhar
2019-10-09 16:19     ` [Intel-wired-lan] " Samudrala, Sridhar
2019-10-09  0:49 ` Jakub Kicinski
2019-10-09  0:49   ` [Intel-wired-lan] " Jakub Kicinski
2019-10-09  6:29   ` Samudrala, Sridhar
2019-10-09  6:29     ` [Intel-wired-lan] " Samudrala, Sridhar
2019-10-09 16:53     ` Jakub Kicinski
2019-10-09 16:53       ` [Intel-wired-lan] " Jakub Kicinski

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