On Fri, 8 Nov 2024 at 07:07, Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote: > I don't think external bitmap can workaround the performance degradation > problem, because the global lock for the bitmap are the one to blame for > this, it's the same for external or internal bitmap. Not according to my tests: 5 disk RAID5, 64K chunk Test BW IOPS bitmap internal 64M 700KiB/s 174 bitmap internal 128M 702KiB/s 175 bitmap internal 512M 1142KiB/s 285 bitmap internal 1024M 40.4MiB/s 10.3k bitmap internal 2G 66.5MiB/s 17.0k bitmap external 64M 67.8MiB/s 17.3k bitmap external 1024M 76.5MiB/s 19.6k bitmap none 80.6MiB/s 20.6k Single disk 1K 54.1MiB/s 55.4k Single disk 4K 269MiB/s 68.8k Full test logs with system details at: pastebin. com/raw/TK4vWjQu > > Do you know that is there anyone using external bitmap in the real > world? And is there numbers for performance? We'll have to consider > to keep it untill the new lockless bitmap is ready if so. Well I am and it's a royal pain but there isn't much of an alternative.
