From: Jesper Dangaard Brouer <brouer@redhat.com>
To: intel-wired-lan@osuosl.org
Subject: [Intel-wired-lan] [PATCH bpf-next 10/11] i40e: implement AF_XDP zero-copy support for Tx
Date: Tue, 5 Jun 2018 14:43:47 +0200 [thread overview]
Message-ID: <20180605144347.34351ecc@redhat.com> (raw)
In-Reply-To: <20180604120601.18123-11-bjorn.topel@gmail.com>
On Mon, 4 Jun 2018 14:06:00 +0200
Bj?rn T?pel <bjorn.topel@gmail.com> wrote:
> Here, ndo_xsk_async_xmit is implemented. As a shortcut, the existing
> XDP Tx rings are used for zero-copy. This will result in other devices
> doing XDP_REDIRECT to an AF_XDP enabled queue will have its packets
> dropped.
This behavior is problematic, because XDP Tx rings are smp_processor_id
based, and several RX queues can (via proc smp_affinity settings) be
assigned to the same CPU. Thus, other RX-queues (than the AF_XDP
enabled queue) can experience packet drops. And other devices doing
redirect through i40e, which happen to run on a CPU which XDP Tx queue
is "hijacked" will see dropped packets.
Any plans to allocate/create a dedicated TX ring per AF_XDP socket?
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
WARNING: multiple messages have this Message-ID (diff)
From: Jesper Dangaard Brouer <brouer@redhat.com>
To: "Björn Töpel" <bjorn.topel@gmail.com>
Cc: magnus.karlsson@intel.com, magnus.karlsson@gmail.com,
alexander.h.duyck@intel.com, alexander.duyck@gmail.com,
ast@fb.com, daniel@iogearbox.net, netdev@vger.kernel.org,
mykyta.iziumtsev@linaro.org, john.fastabend@gmail.com,
willemdebruijn.kernel@gmail.com, mst@redhat.com,
michael.lundkvist@ericsson.com, jesse.brandeburg@intel.com,
anjali.singhai@intel.com, qi.z.zhang@intel.com,
francois.ozog@linaro.org, ilias.apalodimas@linaro.org,
brian.brooks@linaro.org, andy@greyhouse.net,
michael.chan@broadcom.com, intel-wired-lan@lists.osuosl.org,
brouer@redhat.com
Subject: Re: [PATCH bpf-next 10/11] i40e: implement AF_XDP zero-copy support for Tx
Date: Tue, 5 Jun 2018 14:43:47 +0200 [thread overview]
Message-ID: <20180605144347.34351ecc@redhat.com> (raw)
In-Reply-To: <20180604120601.18123-11-bjorn.topel@gmail.com>
On Mon, 4 Jun 2018 14:06:00 +0200
Björn Töpel <bjorn.topel@gmail.com> wrote:
> Here, ndo_xsk_async_xmit is implemented. As a shortcut, the existing
> XDP Tx rings are used for zero-copy. This will result in other devices
> doing XDP_REDIRECT to an AF_XDP enabled queue will have its packets
> dropped.
This behavior is problematic, because XDP Tx rings are smp_processor_id
based, and several RX queues can (via proc smp_affinity settings) be
assigned to the same CPU. Thus, other RX-queues (than the AF_XDP
enabled queue) can experience packet drops. And other devices doing
redirect through i40e, which happen to run on a CPU which XDP Tx queue
is "hijacked" will see dropped packets.
Any plans to allocate/create a dedicated TX ring per AF_XDP socket?
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2018-06-05 12:43 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-04 12:05 [Intel-wired-lan] [PATCH bpf-next 00/11] AF_XDP: introducing zero-copy support =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 01/11] xsk: moved struct xdp_umem definition =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 02/11] xsk: introduce xdp_umem_page =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2019-03-13 9:39 ` [Intel-wired-lan] [bpf-next, " Jiri Slaby
2019-03-13 9:39 ` [bpf-next,02/11] " Jiri Slaby
2019-03-13 11:23 ` [Intel-wired-lan] [bpf-next, 02/11] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2019-03-13 11:23 ` [bpf-next,02/11] " Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 03/11] net: xdp: added bpf_netdev_command XDP_{QUERY, SETUP}_XSK_UMEM =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` [PATCH bpf-next 03/11] net: xdp: added bpf_netdev_command XDP_{QUERY,SETUP}_XSK_UMEM Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 04/11] xdp: add MEM_TYPE_ZERO_COPY =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 05/11] xsk: add zero-copy support for Rx =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 06/11] net: added netdevice operation for Tx =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 07/11] xsk: wire upp Tx zero-copy functions =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 08/11] i40e: added queue pair disable/enable functions =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2018-06-04 12:05 ` [Intel-wired-lan] [PATCH bpf-next 09/11] i40e: implement AF_XDP zero-copy support for Rx =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:05 ` Björn Töpel
2018-06-04 20:35 ` [Intel-wired-lan] " Alexander Duyck
2018-06-04 20:35 ` Alexander Duyck
2018-06-07 7:40 ` [Intel-wired-lan] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-07 7:40 ` Björn Töpel
2018-06-04 12:06 ` [Intel-wired-lan] [PATCH bpf-next 10/11] i40e: implement AF_XDP zero-copy support for Tx =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:06 ` Björn Töpel
2018-06-04 20:53 ` [Intel-wired-lan] " Alexander Duyck
2018-06-04 20:53 ` Alexander Duyck
2018-06-05 12:43 ` Jesper Dangaard Brouer [this message]
2018-06-05 12:43 ` Jesper Dangaard Brouer
2018-06-05 13:07 ` [Intel-wired-lan] " =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-05 13:07 ` Björn Töpel
2018-06-04 12:06 ` [Intel-wired-lan] [PATCH bpf-next 11/11] samples/bpf: xdpsock: use skb Tx path for XDP_SKB =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?=
2018-06-04 12:06 ` Björn Töpel
2018-06-04 16:38 ` [Intel-wired-lan] [PATCH bpf-next 00/11] AF_XDP: introducing zero-copy support Alexei Starovoitov
2018-06-04 16:38 ` Alexei Starovoitov
2018-06-04 20:29 ` [Intel-wired-lan] " Jeff Kirsher
2018-06-04 20:29 ` Jeff Kirsher
2018-11-14 8:10 ` af_xdp zero copy ideas Michael S. Tsirkin
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