Re: [RFC][PATCH V2 0/4] Btrfs: introduce extent buffer cache to btrfs

Miao Xie <miaox <at> cn.fujitsu.com> writes:

This patchset introduce extent buffer cache to btrfs. The basic idea
is to reduce the search time and the contentions of the extent buffer
lock by re-using the last search result.

I ran stress.sh, xfstests and some other tools to test it, all of them
worked well.

As a performance improvement patchset, of course we did performance test.
Because this patchset is to improve the b+ tree search, in other words,
it improves the performance of the metadata operations, we use file creation
test to measure it. So we ran 10 tasks, and all of them created 100000 files
in their own directories at the same time. As the result, we found this 

patchset

makes btrfs ~20% faster(98s -> 77s).

we can pull this patchset from the URL

	git://github.com/miaoxie/linux-btrfs.git extent-buffer-cache

Thanks
Miao
---

I tested the patchset with aim7's fileserver test with 16 processes on RAM 
emulated SCSI btrfs file system.  I got about 18% speedup in throughput.  The 
workload is a mix of file copy, read, write and file sync.

The contention on btrfs_tree_lock operation is reduced with the patchset, by 
about 8.4% of cpu cycles (from 48.3% to 39.9%).

Miao, I can send you the detailed profile if you are interested.

Thanks.

Tim Chen