sparc: Make sparc64 use scalable lib/iommu-common.c functions

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In iperf experiments running linux as the Tx side (TCP client) with
10 threads results in a severe performance drop when TSO is disabled,
indicating a weakness in the software that can be avoided by using
the scalable IOMMU arena DMA allocation.

Baseline numbers before this patch:
   with default settings (TSO enabled) :    9-9.5 Gbps
   Disable TSO using ethtool- drops badly:  2-3 Gbps.

After this patch, iperf client with 10 threads, can give a
throughput of at least 8.5 Gbps, even when TSO is disabled.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

...

This commit is contained in:

Sowmini Varadhan 2015-04-09 15:33:31 -04:00 • committed by David S. Miller

parent ff7d37a502

commit bb620c3d39

4 changed files with 128 additions and 242 deletions

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7

arch/sparc/include/asm/iommu_64.h

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172

arch/sparc/kernel/iommu.c

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8

arch/sparc/kernel/iommu_common.h

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181

arch/sparc/kernel/pci_sun4v.c

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