Replace pkdrv with nvnetdrv

Open Ryzee119 opened this issue 3 years ago • 0 comments

This is a replacement network driver that intends to improve network performance of nxdk and replace pktdrv. Will close https://github.com/XboxDev/nxdk/issues/460 and https://github.com/XboxDev/nxdk/issues/129. This work was started by @thrimbor and I kind of took it over.

~Relies on https://github.com/XboxDev/nxdk/pull/610.~

It has a few key improvements over pktdrv:

Zero-copy TX and RX transmission
Automatic scatter gather of TX packets that cross page boundaries so the user doesnt need to worry about it (Up to one page crossing, which should cover all ethernet frame lengths required for 100Mbit)
Multithreaded buffer manager
Supports different ring sizes for TX and RX so you can optimise your application for specifc directions to reduce RAM usage. Defaults to 64/64 which seems like a reasonable all around mode even under heavy loads.

As a comparison running lwip iperf server on the same Xbox and PC network config:

Current master (rx then tx test):

[  4] local 192.168.1.115 port 52244 connected with 192.168.1.113 port 5001
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec  39.4 MBytes  33.0 Mbits/sec
[  4] local 192.168.1.115 port 5001 connected with 192.168.1.113 port 51705
[  4]  0.0-10.3 sec  25.2 KBytes  20.1 Kbits/sec

nvnetdrv (rx then tx test)::

[  4] local 192.168.1.115 port 51764 connected with 192.168.1.113 port 5001
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec   112 MBytes  94.2 Mbits/sec
[  4] local 192.168.1.115 port 5001 connected with 192.168.1.113 port 51715
[  4]  0.0-10.0 sec   111 MBytes  92.9 Mbits/sec

It also performs quite well in full duplex mode (tx/rx in parallel):

[  4] local 192.168.1.115 port 57034 connected with 192.168.1.113 port 5001
[  5] local 192.168.1.115 port 5001 connected with 192.168.1.113 port 51704
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec   108 MBytes  90.3 Mbits/sec
[  5]  0.0-10.0 sec   106 MBytes  88.9 Mbits/sec

Current PRd as draft mainly due to it being a fairly large change and subject to feedback. I have tested this quite extensively and currently use it on my homebrew dashboard in the form of an FTP server.

The lwipopt.h tweak is as per https://lwip.fandom.com/wiki/Tuning_TCP, which improved tx speed from ~60mbits to 90+mbits in my test with nvnetdrv. It made little impact to pktdrv perf.

Send-buffer (TCP_SND_BUF):
... For maximum throughput, set this to the same value as TCP_WND

Also fixes a bug in our network init function. We should be using tcpip_input instead of ethernet_input for OS mode (threaded) operation. Ref https://www.nongnu.org/lwip/2_0_x/group__netif.html#gade5498543e74067f28cc6bef0209e3be

Jul 21 '22 10:07 Ryzee119