Re: Socket Direct Protocol: help (2)

Amir Vadai
2010-04-14T14:31:47Z

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@intel.com>
> 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@lnl.infn.it
>
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