[Gluster-devel] following up on the work underway for improvements in ls-l - looking for the data on the test runs

[Mohit Agrawal]

With these 2 changes, we are getting a good improvement in file creation
and
slight improvement in the "ls-l" operation.

We are still working to improve the same.

To validate the same we have executed below script from 6 different clients
on 24x3 distributed
replicate environment after enabling performance related option

mkdir /gluster-mount/`hostname`
date;
for i in {1..100}
do
echo "directory $i is created" `date`
mkdir /gluster-mount/`hostname`/dir$i
tar -xvf /root/kernel_src/linux-5.4-rc8.tar.xz -C
/gluster-mount/`hostname`/dir$i >/dev/null
done

With no Patch
tar was taking almost 36-37 hours

With Patch
tar is taking almost 26 hours

We were getting a similar kind of improvement in smallfile tool also.

On Tue, Feb 25, 2020 at 1:29 PM Mohit Agrawal <moagrawa at redhat.com> wrote:

> Hi,
> We observed performance is mainly hurt while .glusterfs is having huge
> data.As we know before executing a fop in POSIX xlator it builds an
> internal path based on GFID.To validate the path it call's (l)stat system
> call and while .glusterfs is heavily loaded kernel takes time to lookup
> inode and due to that performance drops
> To improve the same we tried two things with this patch(
> https://review.gluster.org/#/c/glusterfs/+/23783/)
>
> 1) To keep the first level entry always in a cache so that inode lookup
> will be faster       we have to keep open first level fds(00 to ff total
> 256) per brick at the time of starting a brick process. Even in case of
> cache cleanup kernel will not evict first level fds from the cache and
> performance will improve
>
> 2) We tried using "at" based call(lstatat,fstatat,readlinat etc) instead
> of accessing complete path access relative path, these call's were also
> helpful to improve performance.
>
> Regards,
> Mohit Agrawal
>
>
>
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