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Subject: Re: [OMPI devel] PML/ob1 problem
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2009-02-19 08:05:24


George -- any thoughts on this one?

On Feb 11, 2009, at 1:01 AM, Mike Dubman wrote:

>
> Hello guys,
>
> I'm running some experimental tcp btl which implements rdma GET
> method and advertises it in its flags of the btl API.
> The btl`s send() method returns rc=1 to select fast path for PML.
> (this optimization was added in revision 18551 in v1.3)
>
> It seems that in PML/ob1, mca_pml_ob1_send_request_start_rdma()
> function does not treat right such combination (btl GET + fastpath
> rc>0) and going into deadlock, i.e.
>
> +++ pml_ob1_sendreq.c +670
> At this line, sendreq->req_state is 0
>
> +++ pml_ob1_sendreq.c +800
> At this line, if btl has GET method and btl`s send() returned
> fastpath hint - the call to mca_pml_ob1_rndv_completion_request()
> will decrement sendreq->req_state by one, leaving it to -1.
>
> This value of -1 will keep send_request_pml_complete_check() from
> completing request on PML level.
>
> The PML logic (in mca_pml_ob1_send_request_start_rdma) for PUT
> operation initializes req_state to "2" in pml_ob1_sendreq.c +791,
> but leaves req_state to 0 for GET operations.
>
> Please suggest.
>
> Thanks
>
> Mike.
>
>
>
>
>
>
>
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-- 
Jeff Squyres
Cisco Systems