On Monday 08 March 2021 20:55:20 Greg KH wrote:
On Mon, Mar 08, 2021 at 06:57:57PM +0100, Pali Rohár wrote:
From: Alexander Lobakin bloodyreaper@yandex.ru
commit e131a5634830047923c694b4ce0c3b31745ff01b upstream.
gro_cells lib is used by different encapsulating netdevices, such as geneve, macsec, vxlan etc. to speed up decapsulated traffic processing. CPU tag is a sort of "encapsulation", and we can use the same mechs to greatly improve overall DSA performance. skbs are passed to the GRO layer after removing CPU tags, so we don't need any new packet offload types as it was firstly proposed by me in the first GRO-over-DSA variant [1].
The size of struct gro_cells is sizeof(void *), so hot struct dsa_slave_priv becomes only 4/8 bytes bigger, and all critical fields remain in one 32-byte cacheline. The other positive side effect is that drivers for network devices that can be shipped as CPU ports of DSA-driven switches can now use napi_gro_frags() to pass skbs to kernel. Packets built that way are completely non-linear and are likely being dropped without GRO.
This was tested on to-be-mainlined-soon Ethernet driver that uses napi_gro_frags(), and the overall performance was on par with the variant from [1], sometimes even better due to minimal overhead. net.core.gro_normal_batch tuning may help to push it to the limit on particular setups and platforms.
iperf3 IPoE VLAN NAT TCP forwarding (port1.218 -> port0) setup on 1.2 GHz MIPS board:
5.7-rc2 baseline:
[ID] Interval Transfer Bitrate Retr [ 5] 0.00-120.01 sec 9.00 GBytes 644 Mbits/sec 413 sender [ 5] 0.00-120.00 sec 8.99 GBytes 644 Mbits/sec receiver
Iface RX packets TX packets eth0 7097731 7097702 port0 426050 6671829 port1 6671681 425862 port1.218 6671677 425851
With this patch:
[ID] Interval Transfer Bitrate Retr [ 5] 0.00-120.01 sec 12.2 GBytes 870 Mbits/sec 122 sender [ 5] 0.00-120.00 sec 12.2 GBytes 870 Mbits/sec receiver
Iface RX packets TX packets eth0 9474792 9474777 port0 455200 353288 port1 9019592 455035 port1.218 353144 455024
v2:
- Add some performance examples in the commit message;
- No functional changes.
[1] https://lore.kernel.org/netdev/20191230143028.27313-1-alobakin@dlink.ru/
Signed-off-by: Alexander Lobakin bloodyreaper@yandex.ru Signed-off-by: David S. Miller davem@davemloft.net
This patch radically increase network performance on DSA setup.
Please include this patch into stable releases.
I have done following tests:
NAT is a tested Espressobin board (ARM64 Marvell Armada 3720 SoC with Marvell 88E6141 DSA switch) which was configured for IPv4 masquerade. WAN and LAN are another two static boxes on which was running iperf3.
4.19.179 without e131a5634830047923c694b4ce0c3b31745ff01b
WAN --> NAT --> LAN [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.01 sec 440 MBytes 369 Mbits/sec 12 sender [ 5] 0.00-10.00 sec 437 MBytes 367 Mbits/sec receiver
WAN <-- NAT <-- LAN [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 390 MBytes 327 Mbits/sec 90 sender [ 5] 0.00-10.01 sec 388 MBytes 326 Mbits/sec receiver
4.19.179 with e131a5634830047923c694b4ce0c3b31745ff01b
WAN --> NAT --> LAN [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.01 sec 616 MBytes 516 Mbits/sec 18 sender [ 5] 0.00-10.00 sec 613 MBytes 515 Mbits/sec receiver
WAN <-- NAT <-- LAN [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 573 MBytes 480 Mbits/sec 32 sender [ 5] 0.00-10.01 sec 570 MBytes 478 Mbits/sec receiver
5.4.103 without e131a5634830047923c694b4ce0c3b31745ff01b
WAN --> NAT --> LAN [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.01 sec 454 MBytes 380 Mbits/sec 62 sender [ 5] 0.00-10.00 sec 451 MBytes 378 Mbits/sec receiver
WAN <-- NAT <-- LAN [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 425 MBytes 356 Mbits/sec 155 sender [ 5] 0.00-10.01 sec 422 MBytes 354 Mbits/sec receiver
5.4.103 with e131a5634830047923c694b4ce0c3b31745ff01b
WAN --> NAT --> LAN [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.01 sec 604 MBytes 506 Mbits/sec 8 sender [ 5] 0.00-10.00 sec 601 MBytes 504 Mbits/sec receiver
WAN <-- NAT <-- LAN [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 578 MBytes 485 Mbits/sec 79 sender [ 5] 0.00-10.01 sec 575 MBytes 482 Mbits/sec receiver
net/dsa/Kconfig | 1 + net/dsa/dsa.c | 2 +- net/dsa/dsa_priv.h | 3 +++ net/dsa/slave.c | 10 +++++++++- 4 files changed, 14 insertions(+), 2 deletions(-)
So this patch should be applied to the 4.19 and 5.4 stable queues?
Yes! Patch was introduced in 5.8 and applies cleanly for 4.19 and 5.4 stable releases without any modifications. Trying to apply it for 4.14 results in patch conflicts. So I have done tests only for 4.19 and 5.4.
Speed increases like this are always nice to see :)
thanks,
greg k-h