On 4.02.21 г. 13:34 ч., Wang Yugui wrote:

Hi,

quoted

On 4.02.21 г. 5:17 ч., Wang Yugui wrote:

quoted

Hi,

I tried to run btrfs misc-next(5.11-rc6 +81patches) based on linux LTS
5.10.12 with the same other kernel components and the same kernel config.

Better dbench(sync open) result on both Throughput and max_latency.

If i understand correctly you rebased current misc-next to 5.10.12, if
so this means there is something else in the main kernel, that's not
btrfs related which degrades performance, it seems you've got a 300ms
win by running on 5.10 as compared on 5.11-rc6-based misc next, is that
right?

Yes.

I just realized this could also be caused by btrfs code that has already
landed in v5.11-rc1 for example. I.e the main pull req for this release.

maybye some code rather than btrfs in main kernel 5.11.rc6 have degrades
performance.
or maybe just because of different kernel config.
kernel config I used:
https://kojipkgs.fedoraproject.org/packages/kernel/5.11.0/0.rc6.141.eln108/
https://kojipkgs.fedoraproject.org/packages/kernel/5.10.12/200.fc33/

I rebased current misc-next to 5.10.12, so that there is only diff in
btrfs source code.

only 3 minor patch needed for this rebase, there seems no broken kernel API
 change for btrfs between 5.10 and 5.11.
# add-to-5.10  0001-block-add-a-bdev_kobj-helper.patch
# drop-from-btrs-misc-next  0001-block-remove-i_bdev.patch
# fix-to-btrfs-misc-next  	0001-btrfs-bdev_nr_sectors.patch

more patch come into misc-next today, they are yet not rebased/tested.

Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2021/02/04