Messages in this thread | | | Date | Wed, 23 Feb 2011 15:12:41 +0200 | From | Avi Kivity <> | Subject | Re: [RFC PATCH 0/3] Weight-balanced binary tree + KVM growable memory slots using wbtree |
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On 02/22/2011 08:54 PM, Alex Williamson wrote: > This series introduces a new weight-balanced binary tree (wbtree) for > general use. It's largely leveraged from the rbtree, copying it's > rotate functions, while introducing different rebalance and erase > functions. This tree is particularly useful for managing memory > ranges, where it's desirable to have the most likely targets (the > largest ranges) at the top of each subtree. > > Patches 2& 3 go on to convert the KVM memory slots to a growable > array and make use of wbtree for efficient managment. Trying to > exercise the worst case for this data structure, I ran netperf > TCP_RR on an emulated rtl8139 NIC connected directly to the host > via a tap. Both qemu-kvm and the netserver on the host were > pinned to optimal CPUs with taskset. This series resulted in > a 3% improvement for this test. >
In this case, I think most of the faults (at least after the guest was warmed up) missed the tree completely. In this case a weight balanced tree is hardly optimal (it is optimized for hits), so I think you'll see a bigger gain from the mmio fault optimization. You'll probably see most of the gain running mmu intensive tests with ept=0.
> Note that part of why this series is RFC is that the print_tree > function in the last patch is debug code that generates output > for dot. You can copy the output to a file and run: > > dot -Tpdf foo.dot> foo.pdf > > to generate a nice diagram of the tree currently in use. I'll > follow-up with a few examples. Thanks, > > Alex >
-- error compiling committee.c: too many arguments to function
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