From: Jason Gunthorpe <jgg@ziepe.ca>
To: Gal Pressman <galpress@amazon.com>
Cc: RDMA mailing list <linux-rdma@vger.kernel.org>
Subject: Re: ibv_req_notify_cq clarification
Date: Thu, 18 Feb 2021 08:53:39 -0400 [thread overview]
Message-ID: <20210218125339.GY4718@ziepe.ca> (raw)
In-Reply-To: <bd5deec5-8fc6-ccd6-927a-898f6d9ab35b@amazon.com>
On Thu, Feb 18, 2021 at 11:13:43AM +0200, Gal Pressman wrote:
> I'm a bit confused about the meaning of the ibv_req_notify_cq() verb:
> "Upon the addition of a new CQ entry (CQE) to cq, a completion event will be
> added to the completion channel associated with the CQ."
>
> What is considered a new CQE in this case?
> The next CQE from the user's perspective, i.e. any new CQE that wasn't consumed
> by the user's poll cq?
> Or any new CQE from the device's perspective?
new CQE from the device perspective.
> For example, if at the time of ibv_req_notify_cq() call the CQ has received 100
> completions, but the user hasn't polled his CQ yet, when should he be notified?
> On the 101 completion or immediately (since there are completions waiting on the
> CQ)?
101 completion
It is only meaningful to call it when the CQ is empty.
Jason
next prev parent reply other threads:[~2021-02-18 16:17 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-18 9:13 ibv_req_notify_cq clarification Gal Pressman
2021-02-18 12:38 ` Bernard Metzler
2021-02-18 12:47 ` Gal Pressman
2021-02-18 13:59 ` Bernard Metzler
2021-02-18 12:53 ` Jason Gunthorpe [this message]
2021-02-18 15:52 ` Gal Pressman
2021-02-18 16:23 ` Jason Gunthorpe
2021-02-18 18:47 ` Bernard Metzler
2021-02-18 22:22 ` Tom Talpey
2021-02-18 22:51 ` Jason Gunthorpe
2021-02-18 23:07 ` Tom Talpey
2021-02-19 0:45 ` Jason Gunthorpe
2021-02-19 14:31 ` Tom Talpey
2021-02-19 14:42 ` Jason Gunthorpe
2021-02-21 9:25 ` Gal Pressman
2021-02-22 13:46 ` Jason Gunthorpe
2021-02-22 15:36 ` Gal Pressman
2021-02-22 15:55 ` Jason Gunthorpe
2021-02-22 19:24 ` Gal Pressman
2021-02-22 19:37 ` Jason Gunthorpe
2021-02-23 12:18 ` Gal Pressman
2021-02-23 12:38 ` Jason Gunthorpe
2021-02-22 22:41 ` Hefty, Sean
2021-02-23 12:23 ` Gal Pressman
2021-02-23 20:48 ` Hefty, Sean
2021-02-22 18:38 ` Hefty, Sean
2021-02-22 19:26 ` Gal Pressman
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