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Date:   Wed, 22 Sep 2021 11:40:09 +0300
From:   Leon Romanovsky <leon@kernel.org>
To:     Tatyana Nikolova <tatyana.e.nikolova@intel.com>
Cc:     jgg@nvidia.com, dledford@redhat.com, linux-rdma@vger.kernel.org
Subject: Re: [PATCH rdma-core] irdma: Remove optimization algorithm for QP
 doorbell
Message-ID: <YUrr6Vjm/YID9CQv@unreal>
References: <20210920213723.1279-1-tatyana.e.nikolova@intel.com>
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On Mon, Sep 20, 2021 at 04:37:23PM -0500, Tatyana Nikolova wrote:
> Remove optimization algorithm for QP doorbell, because
> without an mfence the algorithm incorrectly skips ringing
> the doorbell. This causes applicaitons like OpenMPI with
> high number of connections to stall waiting for completion.
> 
> Enforcing the order of the write of the WQE valid bit
> and the read of the SQ tail is required by the algorithm,
> but furher investigation is necessary because this does not
> appear sufficient for the algorithm to work. In the meantime,
> remove the doorbell optimization and fix the MPI failures.
> 
> Signed-off-by: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
> ---
>  providers/irdma/uk.c | 29 ++---------------------------
>  1 file changed, 2 insertions(+), 27 deletions(-)
> 

Thanks, applied.