On 01/22/2013 03:16 PM, Gabe Black wrote: > I have been spending some time in the igb driver code to understand what I > would have to change to make more use of the header-split features of the > cards. > > I noticed that header-split is always set to > E1000_SRRCTL_DESCTYPE_HDR_SPLIT_ALWAYS, which translates to setting DESCTYPE > in the SRRCTL register to 101b. > > However, for the i350, and 82576 cards (the two I happen to have), that value > is "Reserved". It took me a while to figure out how that value came about > when I finally took a look at the 82598 datasheet which gives that value as > being "Advanced descriptor header splitting - always use header buffer". > > So my question is there inside knowledge that setting 101b (reserved) on the > i350 and 82576 has the same behavior as the 82598? Or was it just luck? If > there is any documentation or references that you could provide, that would > be much appreciated. > > Thanks, > Gabe Black
Hello Gabe, In regards to your questions the simple answer is yes. We are bot a bit lucky and we do have some inside knowledge since we are able to talk with the hardware designers. It is interesting that you mention the 82598. To the best of my knowledge it does have the same behavior as the igb parts currently have in regards to packet split. However the follow-on to that part, the 82599 does not have the same behavior. This has caused issues that have led us to defeature packet split in both the ixgbe and igb drivers. The changes are already in place in the ixgbe driver, and the next release of the igb driver will no longer make use of the header split feature. Thanks, Alex ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnnow-d2d _______________________________________________ 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
