bcachefs
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Note on the phoronix numbers
🕑 Added 2023-11-04 15:26:48 +0000 UTCPhoronix recently posted some bcachefs benchmarks, and their results looked a bit... off.
Here's what I just got, testing 4k random writes with a similar fio configuration. SSD is a Samsung 970 Evo plus. Default mkfs options for all three filesystems.
xfs: 1 job 456k iops, 8 jobs 548k iops
btrfs: 1 job 112k iops, 8 jobs 113k iops
bcachefs: 1 job 161k, 8 jobs 538k
So comparing bcachefs to xfs - we see much higher CPU usage because we're COW (every write has to allocate, and the extent mapping is much more fragmented because we're doing 4k random writes!) - but we do still scale, and we're able to max out the device with enough jobs.
Comments
Colin O'Brien
Have you reached out? Seems like something they could revise/ correct.
sobkas
And that nasty error with bigger SSD?
John-Gee
If that is the case, will you disable it by default in the kernel?
Kent Overstreet
I suspect a lot of this might be from having CONFIG_BCACHEFS_DEBUG_TRANSACTIONS on by default. hmm...
Scott Bruce
It's not like phoronix are known for their skillful use of or interpretation of benchmark data so this isn't terribly surprising.
Nazar Mokrynskyi
Something somewhere must be different, but if it is reproducible, it must also be fixable.
brunoais
🤔 Then I wonder why the numbers are different
