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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=561881F7.2070304@plumgrid.com \
--to=ast@plumgrid$(echo .)com \
--cc=daniel@iogearbox$(echo .)net \
--cc=davem@davemloft$(echo .)net \
--cc=dho@fastly$(echo .)com \
--cc=edumazet@google$(echo .)com \
--cc=netdev@vger$(echo .)kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox