On Tue, 22 May 2012 19:59:16 +0100 Ben Hutchings <[email protected]> wrote:
> On Tue, 2012-05-22 at 20:39 +0200, Christer Ekholm wrote: > > Stephen Hemminger writes: > > > On Tue, 22 May 2012 11:19:50 -0700 > > > Stephen Hemminger <[email protected]> wrote: > > > > > > > > > I believe the problem is detected here. Check system console log (dmesg). > > > The hardware does not allow receive hashing and checksum offload together > > > in Jumbo mode. > > > > > > /* > > > * IP payload checksum (enabled with jumbos/packet-split when > > > * Rx checksum is enabled) and generation of RSS hash is > > > * mutually exclusive in the hardware. > > > */ > > > if ((netdev->features & NETIF_F_RXCSUM) && > > > (netdev->features & NETIF_F_RXHASH)) { > > > e_err("Jumbo frames cannot be enabled when both receive > > checksum offload and receive hashing are enabled. Disable one of the > > receive offload features before enabling jumbos.\n"); > > > return -EINVAL; > > > } > > > > Yes you are right. > > > > e1000e 0000:05:00.1: eth1: Jumbo frames cannot be enabled when both > > receive checksum offload and receive hashing are enabled. Disable one of > > the receive offload features before enabling jumbos. > > > > How stupid of me to not see that. > > > > After turning rxhash of, setting of mtu to 9000 is possible again. > > > > $ sudo ethtool -K eth1 rxhash off > > > > $ sudo ip link set eth1 mtu 9000 > > > > > > Sorry to have wasted your time. > > It's not a waste of time. > > I think this behaviour is broken: NETIF_F_RXHASH is turned on by default > and user and distribution scripts that set MTU will now be broken until > they know that they need to work around this hardware limitation. And > why should they ever need to know that? > > I think the proper thing to do is to automatically turn off > NETIF_F_RXHASH when the MTU is too high for it to work. The netdev > still keeps track of whether it is 'wanted'. > > Ben. > Agreed. Principal of least surprise says the best thing to do would be turn off features that are performance improvements to allow user to do what they wanted (and turn the error into a warning). ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
