Messages in this thread | | | From | Craig Hada <> | Subject | [PATCH v2 net-next] drivers/net: Enable IOMMU pass through for be2net | Date | Fri, 18 Jan 2013 18:23:14 -0800 |
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This patch sets the coherent DMA mask to 64-bit after the be2net driver has been acknowledged that the system is 64-bit DMA capable. The coherent DMA mask is examined by the Intel IOMMU driver to determine whether to allow pass through context mapping for all devices. With this patch, the be2net driver combined with be2net compatible hardware provides comparable performance to the case where vt-d is disabled. The main use case for this change is to decrease the time necessary to copy virtual machine memory during KVM live migration instantiations.
This patch was tested on a system that enables the IOMMU in non-coherent mode. Two DMA remapper issues were encountered in the previous version and both patches have been committed. commit ea2447f700cab264019b52e2b417d689e052dcfd commit 2e12bc29fc5a12242d68e11875db3dd58efad9ff
The performance of this patch was measured with netperf with vt-d enabled and disabled along with kernel boot parameters intel_iommu and iommu. The command and parameters used in the netperf runs along with results are as follows:
# netperf -c -p 12865 -H 10.10.0.2 -t TCP_STREAM -l 60
vt-d enabled and intel-iommu=on Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % U us/KB us/KB
87380 16384 16384 60.00 4636.58 16.76 -1.00 1.777 -1.000 87380 16384 16384 60.00 4718.79 17.30 -1.00 1.802 -1.000 87380 16384 16384 60.00 4566.91 18.04 -1.00 1.942 -1.000
vt-d enabled Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % U us/KB us/KB
87380 16384 16384 60.00 6837.12 7.21 -1.00 0.518 -1.000 87380 16384 16384 60.00 6956.20 6.38 -1.00 0.450 -1.000 87380 16384 16384 60.00 6903.63 6.75 -1.00 0.481 -1.000
vt-d disabled Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % U us/KB us/KB
87380 16384 16384 60.00 6909.70 6.57 -1.00 0.467 -1.000 87380 16384 16384 60.00 6811.79 6.90 -1.00 0.498 -1.000 87380 16384 16384 60.00 6861.32 6.71 -1.00 0.481 -1.000
vt-d enabled and intel_iommu=on and iommu=pt Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % U us/KB us/KB
87380 16384 16384 60.00 6768.45 7.30 -1.00 0.530 -1.000 87380 16384 16384 60.00 6841.40 7.39 -1.00 0.531 -1.000 87380 16384 16384 60.00 6861.78 5.68 -1.00 0.407 -1.000
Craig Hada (1): drivers/net: Enable IOMMU pass through for be2net
drivers/net/ethernet/emulex/benet/be_main.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-)
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