From: Jinpu Wang <jinpu.wang@cloud.ionos.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Bart Van Assche <bvanassche@acm.org>,
Jack Wang <jinpuwang@gmail.com>,
linux-block@vger.kernel.org, linux-rdma@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
Sagi Grimberg <sagi@grimberg.me>,
Leon Romanovsky <leon@kernel.org>,
Doug Ledford <dledford@redhat.com>,
Danil Kipnis <danil.kipnis@cloud.ionos.com>,
Roman Penyaev <rpenyaev@suse.de>
Subject: Re: [PATCH v6 10/25] rtrs: server: main functionality
Date: Fri, 10 Jan 2020 18:38:46 +0100 [thread overview]
Message-ID: <CAMGffE=vcwto1Jyi21fw4m-H9M0ZjMhzfckXvUz++ComS-tfYw@mail.gmail.com> (raw)
In-Reply-To: <20200107182528.GB26174@ziepe.ca>
On Tue, Jan 7, 2020 at 7:25 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
>
> On Tue, Jan 07, 2020 at 02:19:53PM +0100, Jinpu Wang wrote:
>
> > > How can posting a signaled send prevent that the send queue overflows?
> > > Isn't that something that can only be guaranteed by tracking the number
> > > of WQE's in the send queue?
> > Selective signaling works. All we need to do is signal one WR for
> > every SQ-depth worth of WRs posted. For example, If the SQ depth is
> > 16, we must signal at least one out of every 16. This ensures proper
> > flow control for HW resources.
> > Courtesy: section 8.2.1 of the iWARP Verbs draft
> > http://tools.ietf.org/html/draft-hilland-rddp-verbs-00#section-8.2.1
>
> Not quite. If the SQ depth is 16 and you post 16 things and then
> signal the last one, you *cannot* post new work until you see the
> completion.
>
> More SQ space *ONLY* becomes available upon receipt of a
> completion. This is why you can't have an unsignaled SQ
>
> Jason
Thanks for clarifying.
The HW seems to be very fast to complete WR, that's why never see the problem.
iser has a similar logic, see iser_signal_comp
Jack
next prev parent reply other threads:[~2020-01-10 17:38 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-30 10:29 [PATCH v6 00/25] RTRS (former IBTRS) rdma transport library and RNBD (former IBNBD) rdma network block device Jack Wang
2019-12-30 10:29 ` [PATCH v6 01/25] sysfs: export sysfs_remove_file_self() Jack Wang
2019-12-30 10:29 ` [PATCH v6 02/25] rtrs: public interface header to establish RDMA connections Jack Wang
2019-12-30 19:25 ` Bart Van Assche
2020-01-02 13:35 ` Jinpu Wang
2020-01-02 16:36 ` Bart Van Assche
2020-01-02 16:47 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 03/25] rtrs: private headers with rtrs protocol structs and helpers Jack Wang
2019-12-30 19:48 ` Bart Van Assche
2020-01-02 15:27 ` Jinpu Wang
2020-01-02 17:00 ` Bart Van Assche
2020-01-02 18:26 ` Jason Gunthorpe
2020-01-03 12:31 ` Jinpu Wang
2020-01-03 12:27 ` Jinpu Wang
2019-12-31 0:07 ` Bart Van Assche
2020-01-03 13:48 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 04/25] rtrs: core: lib functions shared between client and server modules Jack Wang
2019-12-30 22:25 ` Bart Van Assche
2020-01-07 12:22 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 05/25] rtrs: client: private header with client structs and functions Jack Wang
2019-12-30 22:51 ` Bart Van Assche
2020-01-07 12:39 ` Jinpu Wang
2019-12-30 23:03 ` Bart Van Assche
2020-01-07 12:39 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 06/25] rtrs: client: main functionality Jack Wang
2019-12-30 23:53 ` Bart Van Assche
2020-01-02 18:23 ` Jason Gunthorpe
2020-01-03 14:30 ` Jinpu Wang
2020-01-03 16:12 ` Bart Van Assche
2019-12-30 10:29 ` [PATCH v6 07/25] rtrs: client: statistics functions Jack Wang
2020-01-02 21:07 ` Bart Van Assche
2020-01-03 14:39 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 08/25] rtrs: client: sysfs interface functions Jack Wang
2020-01-02 21:14 ` Bart Van Assche
2020-01-03 14:59 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 09/25] rtrs: server: private header with server structs and functions Jack Wang
2020-01-02 21:24 ` Bart Van Assche
2020-01-08 16:33 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 10/25] rtrs: server: main functionality Jack Wang
2020-01-02 22:03 ` Bart Van Assche
2020-01-07 13:19 ` Jinpu Wang
2020-01-07 18:25 ` Jason Gunthorpe
2020-01-10 17:38 ` Jinpu Wang [this message]
2019-12-30 10:29 ` [PATCH v6 11/25] rtrs: server: statistics functions Jack Wang
2020-01-02 22:02 ` Bart Van Assche
2020-01-08 12:55 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 12/25] rtrs: server: sysfs interface functions Jack Wang
2020-01-02 22:06 ` Bart Van Assche
2020-01-07 14:40 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 13/25] rtrs: include client and server modules into kernel compilation Jack Wang
2020-01-02 22:11 ` Bart Van Assche
2020-01-03 16:19 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 14/25] rtrs: a bit of documentation Jack Wang
2019-12-30 23:19 ` Bart Van Assche
2020-01-07 14:48 ` Jinpu Wang
2020-01-02 22:21 ` Bart Van Assche
2020-01-07 15:49 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 15/25] rnbd: private headers with rnbd protocol structs and helpers Jack Wang
2020-01-02 22:34 ` Bart Van Assche
2020-01-07 16:53 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 16/25] rnbd: client: private header with client structs and functions Jack Wang
2020-01-02 22:37 ` Bart Van Assche
2020-01-07 17:09 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 17/25] rnbd: client: main functionality Jack Wang
2020-01-02 23:55 ` Bart Van Assche
2020-01-08 14:22 ` Jinpu Wang
2020-01-10 14:45 ` Jinpu Wang
2020-01-10 15:09 ` Roman Penyaev
2020-01-10 15:29 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 18/25] rnbd: client: sysfs interface functions Jack Wang
2020-01-03 0:03 ` Bart Van Assche
2020-01-08 13:06 ` Jinpu Wang
2020-01-08 16:39 ` Bart Van Assche
2020-01-08 16:51 ` Jinpu Wang
2019-12-30 10:29 ` [PATCH v6 19/25] rnbd: server: private header with server structs and functions Jack Wang
2019-12-30 10:29 ` [PATCH v6 20/25] rnbd: server: main functionality Jack Wang
2019-12-30 10:29 ` [PATCH v6 21/25] rnbd: server: functionality for IO submission to file or block dev Jack Wang
2019-12-30 10:29 ` [PATCH v6 22/25] rnbd: server: sysfs interface functions Jack Wang
2019-12-30 10:29 ` [PATCH v6 23/25] rnbd: include client and server modules into kernel compilation Jack Wang
2019-12-30 10:29 ` [PATCH v6 24/25] rnbd: a bit of documentation Jack Wang
2019-12-30 10:29 ` [PATCH v6 25/25] MAINTAINERS: Add maintainers for RNBD/RTRS modules Jack Wang
2019-12-30 12:22 ` Gal Pressman
2020-01-02 8:41 ` Jinpu Wang
2019-12-31 0:11 ` [PATCH v6 00/25] RTRS (former IBTRS) rdma transport library and RNBD (former IBNBD) rdma network block device Bart Van Assche
2020-01-02 8:48 ` Jinpu Wang
2019-12-31 2:39 ` Bart Van Assche
2020-01-02 9:20 ` Jinpu Wang
2020-01-02 18:28 ` Jason Gunthorpe
2020-01-03 12:34 ` Jinpu Wang
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