Date: Fri, 13 Jan 2012 10:00:08 -0800 From: Jack Vogel <jfvogel@gmail.com> To: Iordan Iordanov <iordan@cdf.toronto.edu> Cc: freebsd-bugs@freebsd.org, CDF Admin <admin@cdf.toronto.edu> Subject: Re: unable to set mtu 9000 on Intel x520-t2 adapter Message-ID: <CAFOYbckGkbjpGriqS0wQ0HTT1uB%2BLO63i-nvwT827Ozjjbu6yA@mail.gmail.com> In-Reply-To: <CAFOYbcnRc-K=dkym09eY%2BSk831%2BUhf==oGwWzHAmf82gy%2B5_gw@mail.gmail.com> References: <4F106861.80507@cdf.toronto.edu> <CAFOYbcnRc-K=dkym09eY%2BSk831%2BUhf==oGwWzHAmf82gy%2B5_gw@mail.gmail.com>
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Opps, i meant kern.ipc.nmb* of course... Jack On Fri, Jan 13, 2012 at 9:58 AM, Jack Vogel <jfvogel@gmail.com> wrote: > Its a system resource thing, when you increase to a 9K mtu the driver will > use 9K > mbuf clusters, and with the queues and rings you have its unable to get > enough. > > Very important to look at kern.ipc.nbm* > > In your case nmbjumbo9 is the pool, if you had 4K it would those clusters. > Change the defaults in /etc/sysctl.conf. > > Cheers, > > Jack > > > > On Fri, Jan 13, 2012 at 9:22 AM, Iordan Iordanov <iordan@cdf.toronto.edu>wrote: > >> Hello, >> >> We are testing FreeBSD 9.0-RELEASE on a pair of machines with 10GBASE-T >> Intel x520-t2 adapters interconnected with a straight-through cat6 rj45 >> cable. With mtu 1500, we are achieving aproximately 4 gigabits/s both >> directions as demonstrated with iperf. We wanted to test with mtu 9000 to >> see whether there would be any difference, but we encountered a problem >> setting it. We ran the following commands to alter the MTU to 9000 on the >> two machines (fw3 and fw4): >> >> fw3# ifconfig ix1 192.168.1.100 mtu 9000 >> fw4# ifconfig ix1 192.168.1.200 mtu 9000 >> >> However, instead of getting mtu set to 9000, what we see is the following >> message in the kernel output of both machines: >> >> ix1: Could not setup receive structures >> ix1: Could not setup receive structures >> >> and no traffic getting through. The moment we run: >> >> fw3# ifconfig ix1 192.168.1.100 mtu 1500 >> fw4# ifconfig ix1 192.168.1.200 mtu 1500 >> >> we see: >> >> ix1: link state changed to DOWN >> ix1: link state changed to UP >> >> and traffic starts getting through as before. More information about our >> hardware is: >> >> Motherboard: Supermicro H8DGU-F >> CPU: AMD 6128 8-core >> Memory: 16GB DDR3 >> NICs: Intel x520-t2 10GbaseT adapters >> >> An ifconfig ix1 output for one of the machines: >> >> fw4# ifconfig ix1 >> ix1: flags=8843<UP,BROADCAST,**RUNNING,SIMPLEX,MULTICAST> metric 0 mtu >> 1500 >> >> options=401bb<RXCSUM,TXCSUM,**VLAN_MTU,VLAN_HWTAGGING,JUMBO_** >> MTU,VLAN_HWCSUM,TSO4,VLAN_**HWTSO> >> ether 00:1b:21:d6:19:51 >> inet 192.168.1.200 netmask 0xffffff00 broadcast 192.168.1.255 >> nd6 options=29<PERFORMNUD,**IFDISABLED,AUTO_LINKLOCAL> >> media: Ethernet autoselect (autoselect <full-duplex>) >> status: active >> >> >> Many thanks for any help/action on this! >> >> Sincerely, >> >> Iordan Iordanov >> CDF System Administrator >> University of Toronto >> ______________________________**_________________ >> freebsd-bugs@freebsd.org mailing list >> http://lists.freebsd.org/**mailman/listinfo/freebsd-bugs<http://lists.freebsd.org/mailman/listinfo/freebsd-bugs>; >> To unsubscribe, send any mail to "freebsd-bugs-unsubscribe@**freebsd.org<freebsd-bugs-unsubscribe@freebsd.org> >> " >> > >
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