Messages in this thread | | | Date | Thu, 27 Apr 2017 17:18:55 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH V2] x86/tboot: add an option to disable iommu force on |
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On Thu, Apr 27, 2017 at 07:49:02AM -0700, Shaohua Li wrote: > This is exactly the usage for us. And please note, not everybody should > sacrifice the DMA security. It is only required when the pcie device hits iommu > hardware limitation. In our enviroment, normal network workloads (as high as > 60k pps) are completely ok with iommu enabled. Only the XDP workload, which can > do around 200k pps, is suffering from the problem. So completely forcing iommu > off for some workloads without the performance issue isn't good because of the > DMA security.
How big are the packets in your XDP workload? I also run pps tests for performance measurement on older desktop-class hardware (Xeon E5-1620 v2 and AMD FX 6100) and 10GBit network hardware, and easily get over the 200k pps mark with IOMMU enabled. The Intel system can receive >900k pps and the AMD system is still at ~240k pps.
But my tests only send IPv4/UDP packets with 8bytes of payload, so that is probably different to your setup.
Joerg
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