Re: ixg(4) performances

[christos%astron.com@localhost (Christos Zoulas)]

In article <20140826121728.GL23535%homeworld.netbsd.org@localhost>,
Emmanuel Dreyfus  <manu%netbsd.org@localhost> wrote:
>Hi
>
>ixgb(4) has poor performances, even on latest -current. Here is the
>dmesg output:
>ixg1 at pci5 dev 0 function 1: Intel(R) PRO/10GbE PCI-Express Network
>Driver, Version - 2.3.10
>ixg1: clearing prefetchable bit
>ixg1: interrupting at ioapic0 pin 9
>ixg1: PCI Express Bus: Speed 2.5Gb/s Width x8
>
>The interface is configued with:
>ifconfig ixg1 mtu 9000 tso4 ip4csum tcp4csum-tx udp4csum-tx
>
>And sysctl:
>kern.sbmax = 67108864
>kern.somaxkva = 67108864
>net.inet.udp.sendspace = 2097152
>net.inet.udp.recvspace = 2097152
>net.inet.tcp.sendspace = 2097152
>net.inet.tcp.recvspace = 2097152
>net.inet.tcp.recvbuf_auto = 0
>net.inet.tcp.sendbuf_auto = 0
>
>netperfs shows a maximum performance of 2.3 Gb/s. That let me with
>the feeling that only a PCI lane is used. Is it possible?
>
>I also found this page that tackles the same problem on Linux:
>http://dak1n1.com/blog/7-performance-tuning-intel-10gbe
>
>They tweak the PCI MMRBC. Anyone has an idea of how it could be 
>done on NetBSD? I thought about borrowing code from src/sys/dec/pci/if_dge.c
>but I am not sure what pci_conf_read/pci_conf_write commands should be used.
>
>Any other idea on how to improve performance?

ftp://ftp.supermicro.com/CDR-C2_1.20_for_Intel_C2_platform/Intel/LAN/v15.5/PROXGB/DOCS/SERVER/prform10.htm#Setting_MMRBC