Hi,
On 7/19/23 17:36, Fengnan Chang wrote:
In commit a015434480dc("ext4: send parallel discards on commit
completions"), issue all discard commands in parallel make all
bios could merged into one request, so lowlevel drive can issue
multi segments in one time which is more efficiency, but commit
55cdd0af2bc5 ("ext4: get discard out of jbd2 commit kthread contex")
seems broke this way, let's fix it.
In my test, the time of fstrim fs with multi big sparse file
reduce from 6.7s to 1.3s.
I tried with a 20T sparse file with latest kernel (6.5-rc2+ commit
f7e3a1baf).
truncate -s 20T sparse1.img
mkfs.ext4 sparse1.img
mount -o discard sparse1.img /mnt/
time fstrim /mnt
1. without the patch
[root@localhost ~]# time fstrim /mnt
real 0m13.496s
user 0m0.002s
sys 0m5.202s
2. with the patch
[root@localhost ~]# time fstrim /mnt
real 0m15.956s
user 0m0.000s
sys 0m7.251s
The result is different from your side, could you share your test?
Thanks,
Guoqing
