Messages in this thread | | | From | Alex Williamson <> | Subject | [RFC PATCH 0/3] Weight-balanced binary tree + KVM growable memory slots using wbtree | Date | Tue, 22 Feb 2011 11:54:49 -0700 |
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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.
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
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Alex Williamson (3): kvm: Use weight-balanced tree for memory slot management kvm: Allow memory slot array to grow on demand Weight-balanced tree
arch/ia64/include/asm/kvm_host.h | 4 - arch/ia64/kvm/kvm-ia64.c | 2 arch/powerpc/include/asm/kvm_host.h | 3 arch/s390/include/asm/kvm_host.h | 3 arch/x86/include/asm/kvm_host.h | 5 - arch/x86/include/asm/vmx.h | 6 - arch/x86/kvm/mmu.c | 32 ++++- arch/x86/kvm/x86.c | 6 - include/linux/kvm_host.h | 25 ++++ include/linux/wbtree.h | 55 +++++++++ lib/Makefile | 3 lib/wbtree.c | 170 ++++++++++++++++++++++++++ virt/kvm/kvm_main.c | 226 +++++++++++++++++++++++++++-------- 13 files changed, 464 insertions(+), 76 deletions(-) create mode 100644 include/linux/wbtree.h create mode 100644 lib/wbtree.c
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