Got it~! :)
2021년 1월 22일 (금) 오전 9:55, Chao Yu <[email protected]>님이 작성:
>
> If there is no update in v5, it will be better to include my Reviewed-by
> tag, please note that. :)
>
> Thanks,
>
> On 2021/1/21 21:45, Daeho Jeong wrote:
> > From: Daeho Jeong<[email protected]>
> >
> > We've added a new mount option "checkpoint=merge", which creates a
> > kernel daemon and makes it to merge concurrent checkpoint requests as
> > much as possible to eliminate redundant checkpoint issues. Plus, we
> > can eliminate the sluggish issue caused by slow checkpoint operation
> > when the checkpoint is done in a process context in a cgroup having
> > low i/o budget and cpu shares. To make this do better, we set the
> > default i/o priority of the kernel daemon to "3", to give one higher
> > priority than other kernel threads. The below verification result
> > explains this.
> > The basic idea has come fromhttps://opensource.samsung.com.
> >
> > [Verification]
> > Android Pixel Device(ARM64, 7GB RAM, 256GB UFS)
> > Create two I/O cgroups (fg w/ weight 100, bg w/ wight 20)
> > Set "strict_guarantees" to "1" in BFQ tunables
> >
> > In "fg" cgroup,
> > - thread A => trigger 1000 checkpoint operations
> > "for i in `seq 1 1000`; do touch test_dir1/file; fsync test_dir1;
> > done"
> > - thread B => gererating async. I/O
> > "fio --rw=write --numjobs=1 --bs=128k --runtime=3600 --time_based=1
> > --filename=test_img --name=test"
> >
> > In "bg" cgroup,
> > - thread C => trigger repeated checkpoint operations
> > "echo $$ > /dev/blkio/bg/tasks; while true; do touch test_dir2/file;
> > fsync test_dir2; done"
> >
> > We've measured thread A's execution time.
> >
> > [ w/o patch ]
> > Elapsed Time: Avg. 68 seconds
> > [ w/ patch ]
> > Elapsed Time: Avg. 48 seconds
> >
> > Signed-off-by: Daeho Jeong<[email protected]>
> > Signed-off-by: Sungjong Seo<[email protected]>