From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: netdev@vger.kernel.org, Daniel Borkmann <borkmann@iogearbox.net>,
liu.song.a23@gmail.com, songliubraving@fb.com,
John Fastabend <john.fastabend@gmail.com>
Subject: Re: [bpf-next V2 PATCH 0/8] bpf/xdp: add flags argument to ndo_xdp_xmit and flag flush operation
Date: Sun, 3 Jun 2018 08:17:51 -0700 [thread overview]
Message-ID: <20180603151749.a4pquv2hcouv4bln@ast-mbp> (raw)
In-Reply-To: <152775714013.24817.5067576840614810786.stgit@firesoul>
On Thu, May 31, 2018 at 10:59:42AM +0200, Jesper Dangaard Brouer wrote:
> As I mentioned in merge commit 10f678683e4 ("Merge branch 'xdp_xmit-bulking'")
> I plan to change the API for ndo_xdp_xmit once more, by adding a flags
> argument, which is done in this patchset.
>
> I know it is late in the cycle (currently at rc7), but it would be
> nice to avoid changing NDOs over several kernel releases, as it is
> annoying to vendors and distro backporters, but it is not strictly
> UAPI so it is allowed (according to Alexei).
>
> The end-goal is getting rid of the ndo_xdp_flush operation, as it will
> make it possible for drivers to implement a TXQ synchronization mechanism
> that is not necessarily derived from the CPU id (smp_processor_id).
>
> This patchset removes all callers of the ndo_xdp_flush operation, but
> it doesn't take the last step of removing it from all drivers. This
> can be done later, or I can update the patchset on request.
>
> Micro-benchmarks only show a very small performance improvement, for
> map-redirect around ~2 ns, and for non-map redirect ~7 ns. I've not
> benchmarked this with CONFIG_RETPOLINE, but the performance benefit
> should be more visible given we end-up removing an indirect call.
>
> ---
> V2: Updated based on feedback from Song Liu <songliubraving@fb.com>
Applied, but please send a follow up patch to remove ndo_xdp_flush().
Otherwise this patch set is just a code churn that doing the opposite
of what you're trying to achieve and creating more backport pains.
prev parent reply other threads:[~2018-06-03 15:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-31 8:59 [bpf-next V2 PATCH 0/8] bpf/xdp: add flags argument to ndo_xdp_xmit and flag flush operation Jesper Dangaard Brouer
2018-05-31 8:59 ` [bpf-next V2 PATCH 1/8] xdp: add flags argument to ndo_xdp_xmit API Jesper Dangaard Brouer
2018-05-31 8:59 ` [bpf-next V2 PATCH 2/8] i40e: implement flush flag for ndo_xdp_xmit Jesper Dangaard Brouer
2018-06-04 13:11 ` Daniel Borkmann
2018-05-31 8:59 ` [bpf-next V2 PATCH 3/8] ixgbe: " Jesper Dangaard Brouer
2018-05-31 16:14 ` Song Liu
2018-06-04 13:19 ` Daniel Borkmann
2018-06-04 13:53 ` Jesper Dangaard Brouer
2018-05-31 9:00 ` [bpf-next V2 PATCH 4/8] tun: " Jesper Dangaard Brouer
2018-05-31 16:14 ` Song Liu
2018-05-31 9:00 ` [bpf-next V2 PATCH 5/8] virtio_net: " Jesper Dangaard Brouer
2018-05-31 16:15 ` Song Liu
2018-05-31 9:00 ` [bpf-next V2 PATCH 6/8] xdp: done implementing ndo_xdp_xmit flush flag for all drivers Jesper Dangaard Brouer
2018-05-31 16:16 ` Song Liu
2018-05-31 9:00 ` [bpf-next V2 PATCH 7/8] bpf/xdp: non-map redirect can avoid calling ndo_xdp_flush Jesper Dangaard Brouer
2018-05-31 16:16 ` Song Liu
2018-05-31 9:00 ` [bpf-next V2 PATCH 8/8] bpf/xdp: devmap " Jesper Dangaard Brouer
2018-05-31 16:06 ` Song Liu
2018-06-03 15:17 ` Alexei Starovoitov [this message]
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=20180603151749.a4pquv2hcouv4bln@ast-mbp \
--to=alexei.starovoitov@gmail.com \
--cc=borkmann@iogearbox.net \
--cc=brouer@redhat.com \
--cc=john.fastabend@gmail.com \
--cc=liu.song.a23@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=songliubraving@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
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;
as well as URLs for NNTP newsgroup(s).