Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

Subject: Re: [OMPI devel] Threaded progress for CPCs
From: Pavel Shamis (Pasha) (pasha_at_[hidden])
Date: 2008-05-19 12:39:13


>>>>>
>>>> What about moving posting of receive buffers into main thread. With
>>>> SRQ it is easy: don't post anything in CPC thread. Main thread will
>>>> prepost buffers automatically after first fragment received on the
>>>> endpoint (in btl_openib_handle_incoming()).
>>> It still doesn't guaranty that we will not see RNR (as I understand
>>> we trying to resolve this problem for iwarp?!)
>>>
>>>
>> I don't think that iwarp has SRQ at all. And if it has then it should
>> have HW flow control for it too. I don't see what advantage SRQ without
>> flow control can provide over PPRQ.
I'm agree that HW flow it is no reason for SRQ.
>>
>>> So this solution will cost 1 buffer on each srq ... sounds
>>> acceptable for me. But I don't see too much
>>> difference compared to #1, as I understand we anyway will be need
>>> the pipe for communication with main thread.
>>> so why don't use #1 ?
>>>
>> What communication? No communication at all. Just don't prepost buffers
>> to SRQ during connection establishment. Problem solved (only for SRQ of
>> cause).
As i know Jeff use the pipe for some status update (Jeff, please correct
me if I wrong).
If we still need pipe for communication , I prefer #1.
If we don't have the pipe , I prefer your solution

Pasha