From: Sowmini Varadhan <sowmini.varad...@oracle.com> Date: Thu, 11 Dec 2014 15:21:00 -0500
> All this may be true, but it would also be true for Solaris, which > manages to do line-speed (for the exact same setup), so there must be > some other bottleneck going on? They have DMA mapping interfaces which pre-allocate large batches of mapping at a time. > And fwiw, removing the iommu lock contention out of lockstat > did not make any difference to the throughput, which seems to indicate > that the bottleneck is elsewhere. Like I said, it's in the hypervisor IOMMU interfaces implementing the hardware accesses to flush the hardware and adjust the DMA mappings. The lock just shows because the overhead "bubbles" up to the closest non-hypervisor code. ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
