From: Alexei Starovoitov <ast@plumgrid.com>
To: "Devon H. O'Dell" <dho@fastly.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
davem@davemloft.net, Eric Dumazet <edumazet@google.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH net-next] bpf, skb_do_redirect: clear sender_cpu before xmit
Date: Fri, 9 Oct 2015 20:11:51 -0700 [thread overview]
Message-ID: <561881F7.2070304@plumgrid.com> (raw)
In-Reply-To: <CADe=ujZWjibL39JXM4U32GSHjK_sc6oov1Z0KrTL2dMGryJCjw@mail.gmail.com>
On 10/9/15 9:40 AM, Devon H. O'Dell wrote:
> I like the idea, but it seems unnecessarily magical. What about using
> a bitfield? Then there's just an option bit that is either
> OPTION_NAPI_ID or OPTION_SENDER_CPU. Then the check to set sender_cpu
> in netdev_pick_tx becomes
>
> if (skb->sender_napi_option == OPTION_NAPI_ID || skb->sender_cpu == 0) ..
It's less magical, but slower since two loads from skb and two cmp/jmp
are needed instead of one.
and this is critical path of xmit executed for every skb.
that's why I proposed a sign.
next prev parent reply other threads:[~2015-10-10 3:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-07 8:16 [PATCH net-next] bpf, skb_do_redirect: clear sender_cpu before xmit Daniel Borkmann
2015-10-07 15:46 ` Alexei Starovoitov
2015-10-09 0:50 ` Devon H. O'Dell
2015-10-09 2:35 ` Alexei Starovoitov
2015-10-09 16:40 ` Devon H. O'Dell
2015-10-10 3:11 ` Alexei Starovoitov [this message]
2015-10-09 17:33 ` Daniel Borkmann
2015-10-10 3:19 ` Alexei Starovoitov
2015-10-10 4:38 ` Eric Dumazet
2015-10-10 4:55 ` Alexei Starovoitov
2015-10-10 4:56 ` Alexei Starovoitov
2015-10-10 17:12 ` Eric Dumazet
2015-11-16 18:07 ` Eric Dumazet
2015-10-08 12:07 ` David Miller
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