Before this change, adding an extent map to the extent map tree of an
inode required 2 tree nevigations:
1) doing a tree navigation to search for an existing extent map starting
at the same offset or an extent map that overlaps the extent map we
want to insert;
2) Another tree navigation to add the extent map to the tree (if the
former tree search didn't found anything).
This change just merges these 2 steps into a single one.
While running first few btrfs xfstests I had noticed these trees easily
had a few hundred elements, and then with the following sysbench test it
reached over 1100 elements very often.
Test:
sysbench --test=fileio --file-num=32 --file-total-size=10G \
--file-test-mode=seqwr --num-threads=512 --file-block-size=8192 \
--max-requests=1000000 --file-io-mode=sync [prepare|run]
(fs created with mkfs.btrfs -l 4096 -f /dev/sdb3 before each sysbench
prepare phase)
Before this patch:
run 1 - 41.894Mb/sec
run 2 - 40.527Mb/sec
run 3 - 40.922Mb/sec
run 4 - 49.433Mb/sec
run 5 - 40.959Mb/sec
average - 42.75Mb/sec
After this patch:
run 1 - 48.036Mb/sec
run 2 - 50.21Mb/sec
run 3 - 50.929Mb/sec
run 4 - 46.881Mb/sec
run 5 - 53.192Mb/sec
average - 49.85Mb/sec
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
32193c147f