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In-Reply-To: <bb668d4e-f768-a408-c541-d862d1a2f959@acm.org>
From:   Jinpu Wang <jinpu.wang@cloud.ionos.com>
Date:   Tue, 7 Jan 2020 16:49:52 +0100
Message-ID: <CAMGffEmrHbw8wnsTD0BZV9O38-pJ0Yv7VLkNMJwGoRyOp9Yqfg@mail.gmail.com>
Subject: Re: [PATCH v6 14/25] rtrs: a bit of documentation
To:     Bart Van Assche <bvanassche@acm.org>
Cc:     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>, rpenyaev@suse.de,
        linux-kernel@vger.kernel.org
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On Thu, Jan 2, 2020 at 11:21 PM Bart Van Assche <bvanassche@acm.org> wrote:
>
> On 12/30/19 2:29 AM, Jack Wang wrote:
> > diff --git a/Documentation/ABI/testing/sysfs-class-rtrs-client b/Documentation/ABI/testing/sysfs-class-rtrs-client
> > new file mode 100644
> > index 000000000000..8b219cf6c5c4
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-class-rtrs-client
> > @@ -0,0 +1,190 @@
> > +What:                /sys/class/rtrs-client
> > +Date:                Jan 2020
> > +KernelVersion:       5.6
> > +Contact:     Jack Wang <jinpu.wang@cloud.ionos.com> Danil Kipnis <danil.kipnis@cloud.ionos.com>
> > +Description:
> > +When a user of RTRS API creates a new session, a directory entry with
> > +the name of that session is created under /sys/class/rtrs-client/<session-name>/
>
> Thank you for having included this ABI description. This is very
> helpful. Please follow the format documented in Documentation/ABI/README
> and make sure that all text, including the description, start in column
> 17 and please use tabs for indentation.
will fix.
>
> > diff --git a/drivers/infiniband/ulp/rtrs/README b/drivers/infiniband/ulp/rtrs/README
> > new file mode 100644
> > index 000000000000..59ad60318a18
> > --- /dev/null
> > +++ b/drivers/infiniband/ulp/rtrs/README
> > @@ -0,0 +1,149 @@
> > +****************************
> > +InfiniBand Transport (RTRS)
> > +****************************
> > +
> > +RTRS (InfiniBand Transport) is a reliable high speed transport library
> > +which provides support to establish optimal number of connections
> > +between client and server machines using RDMA (InfiniBand, RoCE, iWarp)
> > +transport. It is optimized to transfer (read/write) IO blocks.
>
> Is it explained somewhere how the optimal number of connections is
> determined and also according to which metric the number of connections
> is optimized? Is the number of connections chosen to minimize latency,
> maximize IOPS or perhaps to optimize yet another metric?
RTRS creates one connection per CPU, optimize for minimizing latency
and maximizing IOPS, I would say.
>
> Thanks,
>
> Bart.
Thanks Bart.