Re: Socket Direct Protocol: help (2)

Steve Wise
2010-04-14T14:54:31Z

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-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>> 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-PK20h7lG/Rc1GQ1Ptb7lUw@public.gmane.org
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
>> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/