From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Brenden Blanco <bblanco@plumgrid.com>,
davem@davemloft.net, netdev@vger.kernel.org,
Martin KaFai Lau <kafai@fb.com>, Ari Saha <as754m@att.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Or Gerlitz <gerlitz.or@gmail.com>,
john.fastabend@gmail.com, hannes@stressinduktion.org,
Thomas Graf <tgraf@suug.ch>, Tom Herbert <tom@herbertland.com>,
Daniel Borkmann <daniel@iogearbox.net>,
brouer@redhat.com, Rana Shahout <rana.shahot@gmail.com>
Subject: Re: [PATCH v6 12/12] net/mlx4_en: add prefetch in xdp rx path
Date: Fri, 8 Jul 2016 17:20:24 +0200 [thread overview]
Message-ID: <20160708172024.4a849b7a@redhat.com> (raw)
In-Reply-To: <1467950191.17638.3.camel@edumazet-glaptop3.roam.corp.google.com>
On Fri, 08 Jul 2016 05:56:31 +0200
Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Thu, 2016-07-07 at 19:15 -0700, Brenden Blanco wrote:
> > XDP programs read and/or write packet data very early, and cache miss is
> > seen to be a bottleneck.
> >
> > Add prefetch logic in the xdp case 3 packets in the future. Throughput
> > improved from 10Mpps to 12.5Mpps. LLC misses as reported by perf stat
> > reduced from ~14% to ~7%. Prefetch values of 0 through 5 were compared
> > with >3 showing dimishing returns.
>
> This is what I feared with XDP.
>
> Instead of making generic changes in the driver(s), we now have 'patches
> that improve XDP numbers'
>
> Careful prefetches make sense in NIC drivers, regardless of XDP being
> used or not.
I feel the same way. Our work on XDP should also benefit the normal
driver usage. Yes, I know that is much much harder to achieve, but it
will be worth it.
I've been playing with prefetch changes to mxl4 (and mlx5) what are generic.
I'll post my patch as RFC.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2016-07-08 15:20 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-08 2:15 [PATCH v6 00/12] Add driver bpf hook for early packet drop and forwarding Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 01/12] bpf: add XDP prog type for early driver filter Brenden Blanco
2016-07-09 8:14 ` Jesper Dangaard Brouer
2016-07-09 13:47 ` Tom Herbert
2016-07-10 13:37 ` Jesper Dangaard Brouer
2016-07-10 17:09 ` Brenden Blanco
2016-07-10 20:30 ` Tom Herbert
2016-07-11 10:15 ` Daniel Borkmann
2016-07-11 12:58 ` Jesper Dangaard Brouer
2016-07-10 20:27 ` Tom Herbert
2016-07-11 11:36 ` Jesper Dangaard Brouer
2016-07-10 20:56 ` Tom Herbert
2016-07-11 16:51 ` Brenden Blanco
2016-07-11 21:21 ` Daniel Borkmann
2016-07-10 21:04 ` Tom Herbert
2016-07-11 13:53 ` Jesper Dangaard Brouer
2016-07-08 2:15 ` [PATCH v6 02/12] net: add ndo to set xdp prog in adapter rx Brenden Blanco
2016-07-10 20:59 ` Tom Herbert
2016-07-11 10:35 ` Daniel Borkmann
2016-07-08 2:15 ` [PATCH v6 03/12] rtnl: add option for setting link xdp prog Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 04/12] net/mlx4_en: add support for fast rx drop bpf program Brenden Blanco
2016-07-09 14:07 ` Or Gerlitz
2016-07-10 15:40 ` Brenden Blanco
2016-07-10 16:38 ` Tariq Toukan
2016-07-09 19:58 ` Saeed Mahameed
2016-07-09 21:37 ` Or Gerlitz
2016-07-10 15:25 ` Tariq Toukan
2016-07-10 16:05 ` Brenden Blanco
2016-07-11 11:48 ` Saeed Mahameed
2016-07-11 21:49 ` Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 05/12] Add sample for adding simple drop program to link Brenden Blanco
2016-07-09 20:21 ` Saeed Mahameed
2016-07-11 11:09 ` Jamal Hadi Salim
2016-07-11 13:37 ` Jesper Dangaard Brouer
2016-07-16 14:55 ` Jamal Hadi Salim
2016-07-08 2:15 ` [PATCH v6 06/12] net/mlx4_en: add page recycle to prepare rx ring for tx support Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 07/12] bpf: add XDP_TX xdp_action for direct forwarding Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 08/12] net/mlx4_en: break out tx_desc write into separate function Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 09/12] net/mlx4_en: add xdp forwarding and data write support Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 10/12] bpf: enable direct packet data write for xdp progs Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 11/12] bpf: add sample for xdp forwarding and rewrite Brenden Blanco
2016-07-08 2:15 ` [PATCH v6 12/12] net/mlx4_en: add prefetch in xdp rx path Brenden Blanco
2016-07-08 3:56 ` Eric Dumazet
2016-07-08 4:16 ` Alexei Starovoitov
2016-07-08 6:56 ` Eric Dumazet
2016-07-08 16:49 ` Brenden Blanco
2016-07-10 20:48 ` Tom Herbert
2016-07-10 20:50 ` Tom Herbert
2016-07-11 14:54 ` Jesper Dangaard Brouer
2016-07-08 15:20 ` Jesper Dangaard Brouer [this message]
2016-07-08 16:02 ` [net-next PATCH RFC] mlx4: RX prefetch loop Jesper Dangaard Brouer
2016-07-11 11:09 ` Jesper Dangaard Brouer
2016-07-11 16:00 ` Brenden Blanco
2016-07-11 23:05 ` Alexei Starovoitov
2016-07-12 12:45 ` Jesper Dangaard Brouer
2016-07-12 16:46 ` Alexander Duyck
2016-07-12 19:52 ` Jesper Dangaard Brouer
2016-07-13 1:37 ` Alexei Starovoitov
2016-07-10 16:14 ` [PATCH v6 00/12] Add driver bpf hook for early packet drop and forwarding Tariq Toukan
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=20160708172024.4a849b7a@redhat.com \
--to=brouer@redhat.com \
--cc=alexei.starovoitov@gmail.com \
--cc=as754m@att.com \
--cc=bblanco@plumgrid.com \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=eric.dumazet@gmail.com \
--cc=gerlitz.or@gmail.com \
--cc=hannes@stressinduktion.org \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=netdev@vger.kernel.org \
--cc=rana.shahot@gmail.com \
--cc=tgraf@suug.ch \
--cc=tom@herbertland.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).