“Why does btrfs get a huge perf hit with background IO work?”
Seems unreasonably slow to me that xterm would take a second to start. My two computers running kernel 6.7 are slow than the machine in the test, both have BTRFS on LUKS.
I tried a cold start of xterm on my older thinkpad with an NVMe drive at ~0.3s.
A cold start on my desktop (also NVMe), 0.08s.
I’m unable to reproduce. I wonder if he might’ve had a fresh install with some background operations grinding on, or some indexing going on.
What background IO load did you run?
I was torrenting porn with good speed.
Incidentally
I was curious about this too. Definitely making me question some of my own thoughts and assumptions about btrfs.
Hold up. I thought btrfs was better than ext4?
Valve decided on Ext4 for Steam Deck and did so probably not just for shits and giggles.
I’m sure this is a specific workload that BTRFS struggles with that others handle just fine.
Other workloads BTRFS will be better, and in others it will be worse. There’s no one size fits all.
It probably has to do with the CoW nature of BTRFS compared to the others which don’t do CoW.
