Re: perftest question

[Ido Shamai <idos-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>]

On 5/17/2011 10:53 PM, ib-x2spCj9RiN0z5UmgcLIfJQ@public.gmane.org wrote:
> Ok.  Thanks for the information.
>
> Is there any particular advantage of using CM over TCP for this information (LID or GID, Qp num, PSN, RKey and the address of the writing buffer)?
>
> Is ib_write_bw an example of RDMA write / RD?
>
> E
>
Except of the iWarp support Steve mentioned I think the rdma_cm has an advantage because it does not required an additional Ethernet connection

to the machines. the test has all it's need.

ib_write_bw is an excellent example of RDMA write with a lot of feature. it can run on RC and UC (no RD).

If you want to view a code of RDMA write, look at ib_write_bw.

Ido

>
> Quoting Ido Shamai <idos-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>:
>
>> Those are actually the same tests, from an IB point of view.
>>
>> the difference between them is that ib_write_bw passes the arguments
>> that need to be known to other side ( LID or GID, Qp num, PSN, RKey and
>> the address of the writing buffer) before post_sending,
>>
>> through TCP connection (using sockets) and the rdma_bw uses the rdma_cm
>> module , which sends those arguments through the IB wire and the SM.
>>
>> rdma_cm is not updated with all the features ib_write_bw have. I will
>> work on this test shortly
>>
>> Ido
>>
>>
>> On 5/17/2011 10:19 PM, ib-x2spCj9RiN0z5UmgcLIfJQ@public.gmane.org wrote:
>>> Just downloaded a snapshot of the perftests.  In the README under  "Test Descriptions" it says:
>>>
>>> rdma_bw.c     streaming BW test with RDMA write transactions
>>>
>>> and
>>>
>>> write_bw.c     BW test with RDMA write transactions
>>>
>>> What is the difference between rdma_bw and write_bw?  I see that  the rdma_bw description contains "streaming" where as write_bw  description does not...  but I am not sure I understand what that  means?
>>>
>>> E
>>>
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>
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