On 06/09/2016 06:03 PM, Alexander Duyck wrote: >> This time I'll reboot the machine, and also try "iommu=pt" as suggested >> in different places for use with 10G NICs. > > That might be a good place to start. > > I'm adding, or at least attempting to, the mailing list and maintainer > for the IOMMU code. You might want to check with the AMD-Vi IOMMU > maintainers to see if they have any other advice as this seems like > something that may have been introduced with changes to the IOMMU as > the ixgbe driver hasn't had any updates to the DMA mapping/unmapping > code in some time and it was working in the 4.4 kernel series and > still works on my system which runs an Intel IOMMU so I am wondering > if this may be something specifically related to changes in the AMD > IOMMU code.
After having rebooted the system with "iommu=pt", the following change of dmesg-output looks curious to me: Without "iommu=pt": > [ 4.869591] iommu: Adding device 0000:04:00.0 to group 13 ... > [ 4.873105] AMD-Vi: Found IOMMU at 0000:00:00.2 cap 0x40 > [ 4.873347] AMD-Vi: Found IOMMU at 0000:40:00.2 cap 0x40 > [ 4.873586] AMD-Vi: Interrupt remapping enabled > [ 4.874108] AMD-Vi: Lazy IO/TLB flushing enabled With "iommu=pt": > [ 4.832580] iommu: Adding device 0000:04:00.0 to group 13 > [ 4.832838] iommu: Using direct mapping for device 0000:04:00.0 ... > [ 4.837074] AMD-Vi: Found IOMMU at 0000:00:00.2 cap 0x40 > [ 4.837305] AMD-Vi: Found IOMMU at 0000:40:00.2 cap 0x40 > [ 4.837535] AMD-Vi: Interrupt remapping enabled > [ 4.838062] AMD-Vi: Lazy IO/TLB flushing enabled > [ 4.838291] PCI-DMA: Using software bounce buffering for IO (SWIOTLB) > [ 4.838533] software IO TLB [mem 0xd3e80000-0xd7e80000] (64MB) mapped at > [ffff8800d3e80000-ffff8800d7e7ffff] I hope that doesn't mean all my network data is now passing through an additional copy-by-CPU... that would be kind of the opposite of what "iommu=pt" seemed to promise :-) One more thing I find curious, but this didn't change with "iommu=pt": > [ 0.000000] AGP: Checking aperture... > [ 0.000000] AGP: No AGP bridge found > [ 0.000000] AGP: Node 0: aperture [bus addr 0x00000000-0x01ffffff] (32MB) > [ 0.000000] AGP: Your BIOS doesn't leave an aperture memory hole > [ 0.000000] AGP: Please enable the IOMMU option in the BIOS setup > [ 0.000000] AGP: This costs you 64MB of RAM > [ 0.000000] AGP: Mapping aperture over RAM [mem 0xcc000000-0xcfffffff] > (65536KB) I checked and the IOMMU-option is definitely enabled in the BIOS setup. So I assume right that these message are irrelevant (since AGP as a whole is irrelevant on this server)? Regards, Lutz Vieweg ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
