[Gluster-devel] libgfapi zero copy write - application in samba, nfs-ganesha

[Raghavendra G]

+sachin.

On Tue, Sep 27, 2016 at 11:23 AM, Raghavendra Gowdappa <rgowdapp at redhat.com>
wrote:

>
>
> ----- Original Message -----
> > From: "Ric Wheeler" <rwheeler at redhat.com>
> > To: "Raghavendra Gowdappa" <rgowdapp at redhat.com>, "Saravanakumar
> Arumugam" <sarumuga at redhat.com>
> > Cc: "Gluster Devel" <gluster-devel at gluster.org>, "Ben Turner" <
> bturner at redhat.com>, "Ben England"
> > <bengland at redhat.com>
> > Sent: Tuesday, September 27, 2016 10:51:48 AM
> > Subject: Re: [Gluster-devel] libgfapi zero copy write - application in
> samba, nfs-ganesha
> >
> > On 09/27/2016 07:56 AM, Raghavendra Gowdappa wrote:
> > > +Manoj, +Ben turner, +Ben England.
> > >
> > > @Perf-team,
> > >
> > > Do you think the gains are significant enough, so that smb and
> nfs-ganesha
> > > team can start thinking about consuming this change?
> > >
> > > regards,
> > > Raghavendra
> >
> > This is a large gain but I think that we might see even larger gains (a
> lot
> > depends on how we implement copy offload :)).
>
> Can you elaborate on what you mean "copy offload"? If it is the way we
> avoid a copy in gfapi (from application buffer), following is the workflow:
>
> <commit>
>
> Work flow of zero copy write operation:
> --------------------------------------
>
> 1) Application requests a buffer of specific size. A new buffer is
> allocated from iobuf pool, and this buffer is passed on to application.
>    Achieved using "glfs_get_buffer"
>
> 2) Application writes into the received buffer, and passes that to
> libgfapi, and libgfapi in turn passes the same buffer to underlying
> translators. This avoids a memcpy in glfs write
>    Achieved using "glfs_zero_write"
>
> 3) Once the write operation is complete, Application must take the
> responsibilty of freeing the buffer.
>    Achieved using "glfs_free_buffer"
>
> </commit>
>
> Do you've any suggestions/improvements on this? I think Shyam mentioned an
> alternative approach (for zero-copy readv I think), let me look up at that
> too.
>
> regards,
> Raghavendra
>
> >
> > Worth looking at how we can make use of it.
> >
> > thanks!
> >
> > Ric
> >
> > >
> > > ----- Original Message -----
> > >> From: "Saravanakumar Arumugam" <sarumuga at redhat.com>
> > >> To: "Gluster Devel" <gluster-devel at gluster.org>
> > >> Sent: Monday, September 26, 2016 7:18:26 PM
> > >> Subject: [Gluster-devel] libgfapi zero copy write - application in
> samba,
> > >>    nfs-ganesha
> > >>
> > >> Hi,
> > >>
> > >> I have carried out "basic" performance measurement with zero copy
> write
> > >> APIs.
> > >> Throughput of zero copy write is 57 MB/sec vs default write 43 MB/sec.
> > >> ( I have modified Ben England's gfapi_perf_test.c for this. Attached
> the
> > >> same
> > >> for reference )
> > >>
> > >> We would like to hear how samba/ nfs-ganesha who are libgfapi users
> can
> > >> make
> > >> use of this.
> > >> Please provide your comments. Refer attached results.
> > >>
> > >> Zero copy in write patch: http://review.gluster.org/#/c/14784/
> > >>
> > >> Thanks,
> > >> Saravana
> >
> >
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-- 
Raghavendra G
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