[rds-devel] comments on the send CQ completion handler

Richard Frank richard.frank at oracle.com
Thu Jan 10 07:29:27 PST 2008


Or Gerlitz wrote:
> Richard Frank wrote:
>> If we are going to change this - let's run a test with out setting up 
>> completion notifications for the rdma ops - and measure interrupt / 
>> context switch rates / CPU util with and with out them.
>
> Rick,
>
> Please note that I don't suggest here to remove the IB_SEND_SIGNALED 
> bit which is the one that causes a completion to be generated for the 
> rdma work request but rather the IB_SEND_SOLICITED bit which causes a 
> completion event to be generated in the receiver side, and since no 
> completion is generated for rdma at the remote side, its useless and 
> confusing to have it the code, that's all...
>
Yes - I understand - just wanted to get the other point considered.
> not asking for completions for the rdma work requests is something else.
>
> Or.
>
>>
>> I believe I did this in some past life - and it shows significant 
>> reductions if we do not generate the extra completions. Who knows - 
>> perhaps they are not needed at all - or maybe things have changed and 
>> they are now !
>>
>> Olaf Kirch wrote:
>>> On Thursday 10 January 2008 12:33, Or Gerlitz wrote:
>>>  
>>>> - IB_SEND_SOLICITED is useless for rdma work requests as there is 
>>>> no matching receive in the other side
>>>>
>>>> - max_unsig_bytes accounting need not be done for the rdma bytes 
>>>> since its pages that came from the user and not allocated by rds
>>>>
>>>> Both are cleanups that improve the code's clarity, If you agree to 
>>>> either/both - I will send a patch early next week
>>>>     
>>>
>>> Yes, please do that. Cleanups always welcome :-)
>>>
>>> Thanks,
>>> Olaf
>>>   
>
>



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