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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

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Why btrfs gets huge perf hit with background IO work? (lemmy.world)

submitted 1 year ago by [email protected] to c/[email protected]

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[–] [email protected] 23 points 1 year ago* (last edited 1 year ago) (1 children)

This screenshot is the only metric where btrfs is incredibly slow.

Bcachefs random and sequential writes and reads are much slower than other filesystems in this benchmark.

I have no idea how the actual real world performance will be. Bcachefs still misses a lot of features so I'll continue to follow the development, hopefully including performance improvements.

Bcachefs sequential write performance in this out-of-the-box comparison was coming in at around half the speed of Btrfs while XFS, F2FS, and EXT4 were the fastest.

https://www.phoronix.com/review/bcachefs-linux-67/2

Edit: The benchmarks were done with a debug variable set, which explains the weak IO.

https://www.phoronix.com/news/Bcachefs-Updated-Linux-6.7

[–] [email protected] 5 points 1 year ago* (last edited 1 year ago) (2 children)

Wait, so the benchmarks mostly contradict claims that bcachefs is almost as fast as ext4 except in application startup time? What kind of test performed for that application startup time benchmark?

[–] [email protected] 25 points 1 year ago (1 children)

Note that in this benchmark, bcachefs had a debug variable turned on that allegedly severely hampered performance. Bcachefs has released an update to disable this variable but Phoronix hasn't redone benchmarks yet. I wouldn't put much value into any bcachefs-related comparisons from this current benchmark.

[–] [email protected] 3 points 1 year ago

Interesting, that hopefully explains the weak IO troughput. Thank you.

[–] [email protected] 3 points 1 year ago* (last edited 1 year ago)

The application startup test is designed to cold-load an application with heavy background IO going on.