linux-kernel - Re: [RFC PATCH 0/3] Weight-balanced binary tree + KVM growable memory slots using wbtree

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Message-ID: <1298401152.5764.63.camel@x201>
Date:	Tue, 22 Feb 2011 11:59:12 -0700
From:	Alex Williamson <alex.williamson@...hat.com>
To:	avi@...hat.com
Cc:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	mtosatti@...hat.com, xiaoguangrong@...fujitsu.com
Subject: Re: [RFC PATCH 0/3] Weight-balanced binary tree + KVM growable
 memory slots using wbtree

On Tue, 2011-02-22 at 11:54 -0700, 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.
> 
> 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,

Attached are examples of the memory slot tree for 2G, 4G, and 8G guests.
Thanks,

Alex


Download attachment "2G.pdf" of type "application/pdf" (49651 bytes)

Download attachment "4G.pdf" of type "application/pdf" (49700 bytes)

Download attachment "8G.pdf" of type "application/pdf" (49662 bytes)