[ofa-general] limit on memory registration

[Dotan Barak]

Rui Machado wrote:
> Hi Dotan
>
>   
>>> is there any limitation on the size that can be registered
>>> (ibv_reg_mr) for communication?
>>> I seem to be limited to 16GB (on 32GB 64bit x86 machine).
>>> Is this normal? Can someone tell me why and/or if there is a workaround?
>>>
>>>       
>> In the device attributes there is an attribute called max_mr_size which
>> indicate the maximum block size
>> that can be registered for a device.
>>     
>
> I have a value of 131056 (printed as an int). How can I decode this?
>   
I have a feeling that you refer to the value of max_mr (am i right?)
>   
>> There is one more limitation which is a device specific for the translation
>> table virtual <-->physical
>> You can check the low level driver of the HW that you are using in order to
>> increase the size
>> of this table.
>>
>> which HW do you use?
>>
>>     
>
> Mellanox
> ca type:25218 (vendor_part_id)
> fw_version : 5.1.400 (fw_ver)
> hw_version : a0 (hw_ver)
>   
The module parameter "num_mtt" control the size of the above described 
table.


Dotan
> Thank you
>