Hi Ilya,

Thanks for the reply. It's basically both i.e. I have a specific project currently and also I am looking to make ceph-fuse faster. 

But for now, let me ask specifically the project based question. In the project I have to write a blk-mq kernel driver for the Ceph client machine. The Ceph client machine will transfer the data to HBA or lets say any embedded device.

My hope is that there can be an alternative and that alternative is to not implement a blk-mq kernel driver and instead do the stuff in userspace. I am trying to avoid writing a blk-mq kernel driver and yet achieve the multi-queue implementation through userspace. Is it possible?

Also AFAIK, the Ceph’s block storage implementation uses a client module and this client module has two implementations librbd (user-space) and krbd (kernel module). I have not gone deep into these client modules. but can librbd help me with this?

Thanks. Looking forward to your reply :-)

BR

On Tue, Jul 14, 2020 at 11:16 PM Ilya Dryomov <idryomov@gmail.com> wrote:
On Mon, Jul 13, 2020 at 8:40 PM Bobby <italienisch1987@gmail.com> wrote:
>
>
> Hi,
>
> I have a question regarding support for multiple BLK-MQ queues for Ceph's RADOS Block Device (RBD). The below given link says that the driver has been using the BLK-MQ interface for a while but not actually multiple queues until now with having a queue per-CPU. A change to not hold onto caps that aren't actually needed.  These improvements and more can be found as part of the Ceph changes for Linux 5.7, which should be released as stable in early June.
>
> https://www.phoronix.com/scan.php?page=news_item&px=Linux-5.7-Ceph-Performance
>
> My question is: Is it possible that through Ceph FS (Filesystem in User Space) I can develop a multi-queue driver for Ceph? Asking because this way I can avoid kernel space. (https://docs.ceph.com/docs/nautilus/start/quick-cephfs/)

[ trimming CCs to dev and ceph-devel ]

Hi Bobby,

I'm not sure what you mean by a "multi-queue driver for Ceph".
blk-mq is the block layer framework, it has nothing to do with
filesystems, whether local sitting on top of a block device (such
as ext4 or XFS) or distributed sitting on top of a network stack
(such as CephFS).

Do you have a specific project in mind or are you just looking to
make ceph-fuse faster?

Thanks,

                Ilya