From: Leon Romanovsky <leon@kernel.org>
To: Dimitris Dimitropoulos <d.dimitropoulos@imatrex.com>
Cc: linux-rdma@vger.kernel.org
Subject: Re: maximum QP size
Date: Sun, 9 Feb 2020 16:57:36 +0200 [thread overview]
Message-ID: <20200209145736.GG13557@unreal> (raw)
In-Reply-To: <CAOc41xHpF5VXK_-L_BeaU9v842BuRd2QTXkZunDKDgiEhixFtg@mail.gmail.com>
On Thu, Feb 06, 2020 at 09:18:00PM -0800, Dimitris Dimitropoulos wrote:
> Hi,
>
> I'm running the ibv_rc_pingpong example and I notice as as rx-depth
> increases the QP create fails, eg at 50k. My understanding is this
> variable controls the number of RECV WR that will be posted in advance
> before SEND WRs are posted.
>
> Is there a limitation on the queue size (the size is unit32_t) and if
> so why ? Also is there a way around it ?
The rx-depth is translated to the size of completion queue buffer.
That buffer used by hardware to post completions - writing completion
queue elements (CQEs) and it is allocated when creating the CQ.
Maximum number of CQEs can be retrieved by the ibv_devinfo -v, see max_cqe field.
Thanks
>
> Regards
> Dimitris
next prev parent reply other threads:[~2020-02-09 14:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 5:18 maximum QP size Dimitris Dimitropoulos
2020-02-09 14:57 ` Leon Romanovsky [this message]
2020-02-10 17:38 ` Dimitris Dimitropoulos
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