Summary: use bonding lacp mode aggregation NIC has performance
problems while intel_immu switch opening
Product: Networking
Version:
Kernel Version: 3.10.0-rc5
Platform: X86
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: bonding&ixgbe
AssignedTo:
ReportedBy: wangyu...@huawei.com,wangweido...@huawei.com
Regression: No
Hi I'am using bonding lacp mode aggregation intel 82599 NIC, there are
performance problems while intel_immu switch is open.
I'am using iperf to test the network speeds.
When intel_immu switch is closed, 4 port after polymerization, the network port
speeds up to 37.6 Gbits / sec,
when intel_immu switch is turned on, 4port After polymerization, the network
port speed only to 28.7 Gbits / sec.
intel_iommu=off
dma_ops = &swiotlb_dma_ops,so map_page = swiotlb_map_page and unmap_page =
swiotlb_unmap_page
intel_iommu=on
dma_ops = &intel_dma_ops,so map_page=intel_map_page and
unmap_page=intel_unmap_page
I think the intel_dma_ops will cost more performance, and the dma_map_page and
dma_map_single_attrs will call map_page(),but the paramters is not same.
Therefor, I do a test
about the time of funcs call map_page or unmap_page.
----------------------------------------------------------------------------
func\count 350(*10000)
dma_map_single_attrs,iommu-off 640000(ns)~1000000(ns)
dma_map_single_attrs,iommu-on 4900000(ns)~5700000(ns)
dma_unmap_single_attrs,iommu-off 330000(ns)~620000(ns)
dma_unmap_single_attrs,iommu-on 3000000(ns)~47000000(ns)
func\count 2900(*10000)
dma_map_page,iommu-off 350000(ns)~610000(ns)
dma_map_page,iommu-on 2160000(ns)~3000000(ns)
dma_unmap_page,iommu-off 345000(ns)~670000(ns)
dma_unmap_page,iommu-on 3000000(ns)~4300000(ns)
----------------------------------------------------------------------------
the time that map and unmap function cost show huge gap when iommu is on and
off.
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