Re: [f2fs-dev] [PATCH] f2fs: flag as supporting buffered async reads

[Jaegeuk Kim]

On 05/31, Juhyung Park wrote:
> Hi Yangtao,
> 
> I remember hearing that f2fs can perform relatively poorly under io_uring,
> nice find.
> 
> I suggest rewriting the commit message though. From the looks of it, it
> might suggest that FMODE_BUF_RASYNC is a magic flag that automatically
> improves performance that can be enabled willy nilly.
> 
> How about something like:
> 
> f2fs uses generic_file_buffered_read(), which supports buffered async
> reads since commit 1a0a7853b901 ("mm: support async buffered reads in
> generic_file_buffered_read()").

Thanks Juhyung,

Applied with a minor motification based on yours. :)

> 
> Match other file-systems and enable it. The read performance has been
> greatly improved under io_uring:
> 
>     167M/s -> 234M/s, Increase ratio by 40%
> 
> Test w/:
>     ./fio --name=onessd --filename=/data/test/local/io_uring_test
>     --size=256M --rw=randread --bs=4k --direct=0 --overwrite=0
>     --numjobs=1 --iodepth=1 --time_based=0 --runtime=10
>     --ioengine=io_uring --registerfiles --fixedbufs
>     --gtod_reduce=1 --group_reporting --sqthread_poll=1
> 
> On Wed, May 31, 2023 at 10:01 PM Yangtao Li via Linux-f2fs-devel
> <linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > After enabling this feature, the read performance has been greatly
> > improved:
> >
> >     167M/s -> 234M/s, Increase ratio by 40%
> >
> > Test w/:
> >     ./fio --name=onessd --filename=/data/test/local/io_uring_test
> >     --size=256M --rw=randread --bs=4k --direct=0 --overwrite=0
> >     --numjobs=1 --iodepth=1 --time_based=0 --runtime=10
> >     --ioengine=io_uring --registerfiles --fixedbufs
> >     --gtod_reduce=1 --group_reporting --sqthread_poll=1
> >
> > Signed-off-by: Lu Hongfei <luhongfei@xxxxxxxx>
> > Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
> > ---
> >  fs/f2fs/file.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 015ed274dc31..23c68ee946e5 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -546,7 +546,7 @@ static int f2fs_file_open(struct inode *inode, struct file *filp)
> >         if (err)
> >                 return err;
> >
> > -       filp->f_mode |= FMODE_NOWAIT;
> > +       filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
> >
> >         return dquot_file_open(inode, filp);
> >  }
> > --
> > 2.39.0
> >
> >
> >
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