After a load tests, I've found the same anomaly with btrfs. I'm using a 80GB btrfs raw device, 16GB memory, 16 CPU threads:
BTRFS: Time 24.026 32 54.584 64 125.520 128 272.835 256 809.038 512 3451.172 1024
So the pinch point happens later than with ZFS, but there seems to be a scaling issue here too.
After a load tests, I've found the same anomaly with btrfs. I'm using a 80GB btrfs raw device, 16GB memory, 16 CPU threads:
BTRFS:
Time
24.026 32
54.584 64
125.520 128
272.835 256
809.038 512
3451.172 1024
So the pinch point happens later than with ZFS, but there seems to be a scaling issue here too.