Re: Socket Direct Protocol: help (2)

[Steve Wise]

Hey Amir,

I don't think this helps because sdp_add_device() will not add rdma 
devices that fail to create fmr pools. 

So I guess you could key off of fmr pool failures and set 
sdp_zcopy_thresh to 0 and allow the device to be used?

But what we really need is sdp support for fastreg_mrs  as an 
alternative to fmrs.


Steve.


Amir Vadai wrote:
> Hi,
>
> FMR are being used only in a special mode called ZCopy.
>
> You could disable this mode by setting the module paramter
> sdp_zcopy_thresh to 0, or by issuing:
> # echo 0 > /sys/module/ib_sdp/parameters/sdp_zcopy_thresh
>
> This means that you won't get the benefits of Zero-copy.
>
> - Amir
>
> On 04/14/2010 11:51 AM, Andrea Gozzelino wrote:
>   
> > On Apr 13, 2010 10:22 PM, "Tung, Chien Tin" <chien.tin.tung@xxxxxxxxx>
> > wrote:
> >
> >   
> >     
> > > > > > Chien, does the NE020 support FMRs? I looked at the nes ofed-1.5
> > > > > > code
> > > > > > and it appears to do nothing in the map_phys_fmr functions.
> > > > > >
> > > > > >           
> > > > > >             
> > > > > We never implemented map_phys_fmr. Is it relevant to the # of SGEs?
> > > > >
> > > > >         
> > > > >           
> > > > No, but SDP uses FMRs. I don't think it will run without FMR support.
> > > >
> > > >       
> > > >         
> > > Good to know.  Thanks.
> > >
> > > Chien
> > >
> > >
> > >     
> > >       
> > Hi Steve and Chien,
> >
> > I understand that NE020 cards have problem with SDP connected with
> > map_phy_fmr (FMR stands for Fast Memory Region).
> > Is it possible to solve/fix this point?
> > If yes, have you an idea about the time that is necessary to code
> > development/build?
> > If no, can you suggest me a card that supports SDP protocol?
> >
> > I work on NE020 cards from February 2010 for an INFN experimental
> > proposal, called REDIGO (Read out at 10 Gbits/s), about the data
> > acquisition and movement systems. The covergence of storage protocols
> > around 10 Gigabits/s Ethernet protocols shows that one way could be the
> > Remote Direct Memory Access (RDMA). The goals are the investigations of
> > latency time, the throughput, the buffer size schemes and finally the
> > global event building bandwidth.
> >
> > Do you know if NE020 cards have problems with librdma (RDMA procedures,
> > in general) and / or with MPI versions?
> >
> > Thank you very much,
> > Andrea
> >
> > Andrea Gozzelino
> >
> > INFN - Laboratori Nazionali di Legnaro	(LNL)
> > Viale dell'Universita' 2
> > I-35020 - Legnaro (PD)- ITALIA
> > Tel: +39 049 8068346
> > Fax: +39 049 641925
> > Mail: andrea.gozzelino@xxxxxxxxxxx			
> >
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> >     
>
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