Ted and all,
While using this FFSB test profile:
http://btrfs.boxacle.net/repository/raid/2010-04-14_2004//ext4-2.6.34-rc3-nobarrier//btrfs1.ffsb.random_writes_odirect__threads_0128.10-04-21_17.38.39/benchmark/profile
(The profile is 128 threads of all odirect random writes. )
on my raid box I am seeing (via Darricks block_barrier tracepoint) right
about 32 barriers per second.
Initial analysis using perf shows kdmflush as the cause. I will continue
to look into this.
Thanks,
Keith Mannthey
LTC FS-Dev