From: Sowmini Varadhan Date: Thu, 9 Apr 2015 19:33:31 +0000 (-0400) Subject: sparc: Make sparc64 use scalable lib/iommu-common.c functions X-Git-Tag: omap-for-v4.1/fixes-rc1~93^2^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bb620c3d3925aec0ed4f21010c86df08ec18a8c7;p=pandora-kernel.git sparc: Make sparc64 use scalable lib/iommu-common.c functions 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 Acked-by: Benjamin Herrenschmidt Signed-off-by: David S. Miller --- Reading git-diff-tree failed