From: "Björn Töpel" <bjorn.topel@gmail.com>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>
Cc: Netdev <netdev@vger.kernel.org>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
bpf <bpf@vger.kernel.org>,
"Magnus Karlsson" <magnus.karlsson@gmail.com>,
"Karlsson, Magnus" <magnus.karlsson@intel.com>,
"Jonathan Lemon" <jonathan.lemon@gmail.com>,
"Edward Cree" <ecree@solarflare.com>,
"Toke Høiland-Jørgensen" <thoiland@redhat.com>,
"Andrii Nakryiko" <andrii.nakryiko@gmail.com>
Subject: Re: [PATCH bpf-next v3 0/6] Introduce the BPF dispatcher
Date: Wed, 11 Dec 2019 13:38:01 +0100 [thread overview]
Message-ID: <CAJ+HfNiH4KUO-MXm3L8pka3dECC1S6rHUJ9NoMfyrhPD+9s9nw@mail.gmail.com> (raw)
In-Reply-To: <CAJ+HfNjZnxrgYtTzbqj2VOP+5A81UW-7OKoReT0dMVBT0fQ1pg@mail.gmail.com>
On Mon, 9 Dec 2019 at 18:42, Björn Töpel <bjorn.topel@gmail.com> wrote:
>
[...]
> > You mentioned in the earlier version that this would impact the time it
> > takes to attach an XDP program. Got any numbers for this?
> >
>
> Ah, no, I forgot to measure that. I'll get back with that. So, when a
> new program is entered or removed from dispatcher, it needs to be
> re-jited, but more importantly -- a text poke is needed. I don't know
> if this is a concern or not, but let's measure it.
>
Toke, I tried to measure the impact, but didn't really get anything
useful out. :-(
My concern was mainly that text-poking is a point of contention, and
it messes with the icache. As for contention, we're already
synchronized around the rtnl-lock. As for the icache-flush effects...
well... I'm open to suggestions how to measure the impact in a useful
way.
>
> Björn
>
> > -Toke
> >
next prev parent reply other threads:[~2019-12-11 12:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-09 13:55 [PATCH bpf-next v3 0/6] Introduce the BPF dispatcher Björn Töpel
2019-12-09 13:55 ` [PATCH bpf-next v3 1/6] bpf: move trampoline JIT image allocation to a function Björn Töpel
2019-12-09 13:55 ` [PATCH bpf-next v3 2/6] bpf: introduce BPF dispatcher Björn Töpel
2019-12-10 5:50 ` Alexei Starovoitov
2019-12-10 5:54 ` Björn Töpel
2019-12-09 13:55 ` [PATCH bpf-next v3 3/6] bpf, xdp: start using the BPF dispatcher for XDP Björn Töpel
2019-12-09 13:55 ` [PATCH bpf-next v3 4/6] bpf: start using the BPF dispatcher in BPF_TEST_RUN Björn Töpel
2019-12-09 13:55 ` [PATCH bpf-next v3 5/6] selftests: bpf: add xdp_perf test Björn Töpel
2019-12-10 11:05 ` Jesper Dangaard Brouer
2019-12-10 11:56 ` Björn Töpel
2019-12-09 13:55 ` [PATCH bpf-next v3 6/6] bpf, x86: align dispatcher branch targets to 16B Björn Töpel
2019-12-09 15:00 ` [PATCH bpf-next v3 0/6] Introduce the BPF dispatcher Toke Høiland-Jørgensen
2019-12-09 17:42 ` Björn Töpel
2019-12-11 12:38 ` Björn Töpel [this message]
2019-12-11 13:17 ` Toke Høiland-Jørgensen
2019-12-09 17:00 ` Jesper Dangaard Brouer
2019-12-09 17:45 ` Björn Töpel
2019-12-09 19:50 ` Jesper Dangaard Brouer
2019-12-10 19:28 ` Samudrala, Sridhar
2019-12-10 20:04 ` Björn Töpel
2019-12-10 19:59 ` Björn Töpel
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