Hi,
在 2024/11/09 6:19, Dragan Milivojević 写道:
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
This is not what I expected, can you give the tests procedures in
details? Including test machine, create the array and test scrpits.
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.
Bitmap file will be removed, the way it's implemented is problematic. If
you have plans to upgrade kernel to v6.13+, I can keep it for now,
untill the other lockless bitmap is ready.
Thanks,
Kuai
.
