From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: "Samudrala, Sridhar" <sridhar.samudrala@intel.com>
Cc: "Karlsson, Magnus" <magnus.karlsson@intel.com>,
"Björn Töpel" <bjorn.topel@intel.com>,
Netdev <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
intel-wired-lan <intel-wired-lan@lists.osuosl.org>,
"Fijalkowski, Maciej" <maciej.fijalkowski@intel.com>,
"Herbert, Tom" <tom.herbert@intel.com>
Subject: Re: FW: [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue
Date: Wed, 9 Oct 2019 18:06:53 -0700 [thread overview]
Message-ID: <CAADnVQ+CH1YM52+LfybLS+NK16414Exrvk1QpYOF=HaT4KRaxg@mail.gmail.com> (raw)
In-Reply-To: <2032d58c-916f-d26a-db14-bd5ba6ad92b9@intel.com>
On Wed, Oct 9, 2019 at 12:12 PM Samudrala, Sridhar
<sridhar.samudrala@intel.com> wrote:
> >> 34.57% xdpsock xdpsock [.] main
> >> 17.19% ksoftirqd/1 [kernel.vmlinux] [k] ___bpf_prog_run
> >> 13.12% xdpsock [kernel.vmlinux] [k] ___bpf_prog_run
> >
> > That must be a bad joke.
> > The whole patch set is based on comparing native code to interpreter?!
> > It's pretty awesome that interpreter is only 1.5x slower than native x86.
> > Just turn the JIT on.
>
> Thanks Alexei for pointing out that i didn't have JIT on.
> When i turn it on, the performance improvement is a more modest 1.5x
> with rxdrop and 1.2x with l2fwd.
I want to see perf reports back to back with proper performance analysis.
> >
> > Obvious Nack to the patch set.
> >
>
> Will update the patchset with the right performance data and address
> feedback from Bjorn.
> Hope you are not totally against direct XDP approach as it does provide
> value when an AF_XDP socket is bound to a queue and a HW filter can
> direct packets targeted for that queue.
I used to be in favor of providing "prog bypass" for af_xdp,
because of anecdotal evidence that it will make af_xdp faster.
Now seeing the numbers and the way they were collected
I'm against such bypass.
I want to see hard proof that trivial bpf prog is actually slowing things down
before reviewing any new patch sets.
next prev parent reply other threads:[~2019-10-10 1:07 UTC|newest]
Thread overview: 42+ 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 ` [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 ` [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue Sridhar Samudrala
2019-10-08 6:58 ` Toke Høiland-Jørgensen
2019-10-08 8:47 ` Björn Töpel
2019-10-08 8:48 ` Björn Töpel
2019-10-08 9:04 ` Toke Høiland-Jørgensen
2019-10-08 8:05 ` Björn Töpel
2019-10-09 16:32 ` Samudrala, Sridhar
2019-10-09 1:20 ` Alexei Starovoitov
[not found] ` <3ED8E928C4210A4289A677D2FEB48235140134CE@fmsmsx111.amr.corp.intel.com>
2019-10-09 16:53 ` FW: " Samudrala, Sridhar
2019-10-09 17:17 ` Alexei Starovoitov
2019-10-09 19:12 ` Samudrala, Sridhar
2019-10-10 1:06 ` Alexei Starovoitov [this message]
2019-10-18 18:40 ` Samudrala, Sridhar
2019-10-18 19:22 ` Toke Høiland-Jørgensen
2019-10-19 0:14 ` Alexei Starovoitov
2019-10-19 0:45 ` Samudrala, Sridhar
2019-10-19 2:25 ` Alexei Starovoitov
2019-10-20 10:14 ` Toke Høiland-Jørgensen
2019-10-20 17:12 ` [Intel-wired-lan] " Björn Töpel
2019-10-21 20:10 ` Samudrala, Sridhar
2019-10-21 22:34 ` Alexei Starovoitov
2019-10-22 19:06 ` Samudrala, Sridhar
2019-10-23 17:42 ` Alexei Starovoitov
2019-10-24 18:12 ` Samudrala, Sridhar
2019-10-25 7:42 ` Björn Töpel
2019-10-31 22:38 ` Samudrala, Sridhar
2019-10-31 23:15 ` Alexei Starovoitov
2019-11-01 0:21 ` Jakub Kicinski
2019-11-01 18:31 ` Samudrala, Sridhar
2019-11-04 2:08 ` dan
2019-10-25 9:07 ` Björn Töpel
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 8:05 ` Björn Töpel
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 8:05 ` Björn Töpel
2019-10-08 8:05 ` [PATCH bpf-next 0/4] Enable direct receive on AF_XDP sockets Björn Töpel
2019-10-09 16:19 ` Samudrala, Sridhar
2019-10-09 0:49 ` Jakub Kicinski
2019-10-09 6:29 ` Samudrala, Sridhar
2019-10-09 16:53 ` Jakub Kicinski
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