Re: [PATCH 0/3] zone-append support in aio and io-uring

[Javier GonzÃlez]

On 18.06.2020 10:32, Matias BjÃrling wrote:
> On 18/06/2020 10.27, Javier GonzÃlez wrote:
> > On 18.06.2020 10:04, Matias BjÃrling wrote:
> > > On 17/06/2020 19.23, Kanchan Joshi wrote:
> > > > This patchset enables issuing zone-append using aio and io-uring 
> > > > direct-io interface.
> > > >
> > > > For aio, this introduces opcode IOCB_CMD_ZONE_APPEND. 
> > > > Application uses start LBA
> > > > of the zone to issue append. On completion 'res2' field is used 
> > > > to return
> > > > zone-relative offset.
> > > >
> > > > For io-uring, this introduces three opcodes: 
> > > > IORING_OP_ZONE_APPEND/APPENDV/APPENDV_FIXED.
> > > > Since io_uring does not have aio-like res2, cqe->flags are 
> > > > repurposed to return zone-relative offset
> > >
> > > Please provide a pointers to applications that are updated and 
> > > ready to take advantage of zone append.
> >
> > Good point. We are posting a RFC with fio support for append. We wanted
> > to start the conversation here before.
> >
> > We can post a fork for improve the reviews in V2.
>
> Christoph's response points that it is not exactly clear how this 
> matches with the POSIX API.

Yes. We will address this.
> fio support is great - but I was thinking along the lines of 
> applications that not only benchmark performance. fio should be part 
> of the supported applications, but should not be the sole reason the 
> API is added.

Agree. It is a process with different steps. We definitely want to have
the right kernel interface before pushing any changes to libraries and /
or applications. These will come as the interface becomes more stable.

To start with xNVMe will be leveraging this new path. A number of
customers are leveraging the xNVMe API for their applications already.

Thanks,
Javier