From: "Samudrala, Sridhar" <sridhar.samudrala@intel.com>
To: bjorn.topel@gmail.com
Cc: alexei.starovoitov@gmail.com, bjorn.topel@intel.com,
bpf@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
jakub.kicinski@netronome.com, maciej.fijalkowski@intel.com,
magnus.karlsson@intel.com, netdev@vger.kernel.org,
sridhar.samudrala@intel.com, toke@redhat.com,
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 15:38:42 -0700 [thread overview]
Message-ID: <2e27b8d9-4615-cd8d-93de-2adb75d8effa@intel.com> (raw)
In-Reply-To: <CAJ+HfNigHWVk2b+UJPhdCWCTcW=Eh=yfRNHg4=Fr1mv98Pq=cA@mail.gmail.com>
[...]
> >
> > With mitigations ON
> > -------------------
> > Samples: 6K of event 'cycles', 4000 Hz, Event count (approx.): 5646512726
> > bpf_prog_3c8251c7e0fef8db bpf_prog_3c8251c7e0fef8db [Percent: local period]
> > 45.05 push %rbp
> > 0.02 mov %rsp,%rbp
> > 0.03 sub $0x8,%rsp
> > 22.09 push %rbx
> [...]
> >
> > Do you see any issues with this data? With mitigations ON push %rbp and push %rbx overhead seems to
> > be pretty high.
> That's sample skid from the retpoline thunk when entring the XDP
> program. Pretty expensive push otherwise! :-)
> Another thought; Disclaimer: I'm no spectrev2 expert, and probably not
> getting the mitigations well enough. So this is me trying to swim at
> the deep end! Would it be possible to avoid the retpoline when
> entering the XDP program. At least for some XDP program that can be
> proved "safe"? If so, PeterZ's upcoming static_call could be used from
> the driver side.
Alexei, Jakub
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.
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
-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: Thu, 31 Oct 2019 15:38:42 -0700 [thread overview]
Message-ID: <2e27b8d9-4615-cd8d-93de-2adb75d8effa@intel.com> (raw)
In-Reply-To: <CAJ+HfNigHWVk2b+UJPhdCWCTcW=Eh=yfRNHg4=Fr1mv98Pq=cA@mail.gmail.com>
[...]
> >
> > With mitigations ON
> > -------------------
> > Samples: 6K of event 'cycles', 4000 Hz, Event count (approx.): 5646512726
> > bpf_prog_3c8251c7e0fef8db bpf_prog_3c8251c7e0fef8db [Percent: local period]
> > 45.05 push %rbp
> > 0.02 mov %rsp,%rbp
> > 0.03 sub $0x8,%rsp
> > 22.09 push %rbx
> [...]
> >
> > Do you see any issues with this data? With mitigations ON push %rbp and push %rbx overhead seems to
> > be pretty high.
> That's sample skid from the retpoline thunk when entring the XDP
> program. Pretty expensive push otherwise! :-)
> Another thought; Disclaimer: I'm no spectrev2 expert, and probably not
> getting the mitigations well enough. So this is me trying to swim at
> the deep end! Would it be possible to avoid the retpoline when
> entering the XDP program. At least for some XDP program that can be
> proved "safe"? If so, PeterZ's upcoming static_call could be used from
> the driver side.
Alexei, Jakub
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.
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
-Sridhar
next prev parent reply other threads:[~2019-10-31 22:38 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 [this message]
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
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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