Hi Jan, all, > Hi! > On Fri 19-07-24 19:43:25, Petr Vorel wrote: > > LTP AIO DIO tests aiodio_sparse.c [1] and dio_sparse.c [2] (using [3]) > > slowed down on kernel 6.6 on Btrfs and XFS, when run with default > > parameters. These tests create 100 MB sparse file and write zeros (using > > libaio or O_DIRECT) while 16 other processes reads the buffer and check > > only zero is there. > So the performance of this test is irrelevant because combining buffered > reads with direct IO writes was always in "better don't do it" territory. > Definitely not if you care about perfomance. Thanks a lot for having a look, Jan! > > Runtime of this particular setup (i.e. 100 MB file) on Btrfs and XFS on the > > same system slowed down 9x (6.5: ~1 min 6.6: ~9 min). Ext4 is not affected. > > (Non default parameter creates much smaller file, thus the change is not that > > obvious). > But still it's kind of curious what caused the 9x slow down. So I'd be > curious to know the result of the bisection :). Thanks for report! I'm already working on it, report soon. Kind regards, Petr > Honza
