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From: "Samudrala, Sridhar" <sridhar.samudrala@intel.com>
To: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: bjorn.topel@gmail.com, alexei.starovoitov@gmail.com,
	bjorn.topel@intel.com, bpf@vger.kernel.org,
	intel-wired-lan@lists.osuosl.org, maciej.fijalkowski@intel.com,
	magnus.karlsson@intel.com, netdev@vger.kernel.org,
	toke@redhat.com, tom.herbert@intel.com,
	David Miller <davem@davemloft.net>
Subject: Re: Re: [Intel-wired-lan] FW: [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue
Date: Fri, 1 Nov 2019 11:31:11 -0700	[thread overview]
Message-ID: <8481fe0a-fa7b-c689-1e51-1a3253176509@intel.com> (raw)
In-Reply-To: <20191031172148.0290b11f@cakuba.netronome.com>

On 10/31/2019 5:21 PM, Jakub Kicinski wrote:
> On Thu, 31 Oct 2019 15:38:42 -0700, Samudrala, Sridhar wrote:
>> Do you think it will be possible to avoid this overhead when mitigations are turned ON?
>> The other part of the overhead is going through the redirect path.
> 
> Yes, you should help Maciej with the XDP bulking.
> 
>> 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
> 
> This logic baffles me. I absolutely hate when people repost patches
> after I nack them without even as much as mentioning my objections in
> the cover letter.

Sorry if you got the impression that i didn't take your feedback. I CCed you
and also included the kernel rxdrop data that you requested in the original
series.

> 
> My concern was that we want the applications to encode fast path logic
> in BPF and load that into the kernel. So your patch works fundamentally
> against that goal:

So looks like you are saying that the fundamental requirement is that all AF_XDP
packets need to go via a BPF program.

The reason i proposed direct receive is because of the overhead we are seeing
with going via BPF program for apps that want to receive all the packets on a
specific queue.

I agree that there is work going on to reduce this overhead with bulking and avoiding
the retpoline.
We can revisit after these optimizations get in and then see if it is still useful
to provide a direct receive option.

-Sridhar

WARNING: multiple messages have this Message-ID (diff)
From: Samudrala, Sridhar <sridhar.samudrala@intel.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: Fri, 1 Nov 2019 11:31:11 -0700	[thread overview]
Message-ID: <8481fe0a-fa7b-c689-1e51-1a3253176509@intel.com> (raw)
In-Reply-To: <20191031172148.0290b11f@cakuba.netronome.com>

On 10/31/2019 5:21 PM, Jakub Kicinski wrote:
> On Thu, 31 Oct 2019 15:38:42 -0700, Samudrala, Sridhar wrote:
>> Do you think it will be possible to avoid this overhead when mitigations are turned ON?
>> The other part of the overhead is going through the redirect path.
> 
> Yes, you should help Maciej with the XDP bulking.
> 
>> 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
> 
> This logic baffles me. I absolutely hate when people repost patches
> after I nack them without even as much as mentioning my objections in
> the cover letter.

Sorry if you got the impression that i didn't take your feedback. I CCed you
and also included the kernel rxdrop data that you requested in the original
series.

> 
> My concern was that we want the applications to encode fast path logic
> in BPF and load that into the kernel. So your patch works fundamentally
> against that goal:

So looks like you are saying that the fundamental requirement is that all AF_XDP
packets need to go via a BPF program.

The reason i proposed direct receive is because of the overhead we are seeing
with going via BPF program for apps that want to receive all the packets on a
specific queue.

I agree that there is work going on to reduce this overhead with bulking and avoiding
the retpoline.
We can revisit after these optimizations get in and then see if it is still useful
to provide a direct receive option.

-Sridhar

  reply	other threads:[~2019-11-01 18:31 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
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 [this message]
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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