Replaced fixed window size for walkchangerevs with an increasing one. Window sizes starts at 8 (for good interactiveness) and doubles with each window until it is 512, which seems to be the maximum efficient value.

#!/bin/sh

hg init
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "0 0"
touch b
hg add b
rm b
hg commit -A -m"comment #1" -d "0 0"