From: Peter Chinetti <peter.chinetti-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Christoph Lameter <cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>,
Anuj Kalia
<anujkaliaiitd-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: When does IB Multicast drop?
Date: Wed, 25 Nov 2015 11:10:46 -0600 [thread overview]
Message-ID: <5655EB96.2090600@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1511251007020.31676-wcBtFHqTun5QOdAKl3ChDw@public.gmane.org>
> Correct. But multicast packets are droped at the QP receive level if the
> app does not provide enough buffers to accept the data stream. The
> bufers can easily be overrun if one does not code carefully given that
> the maximum number of those is 16K or so. These drops occurs silently.
> Currently there is no accounting for these drops in the upstream kernel.
How about when one of the destinations for the multicast group has its
connection to the switch overloaded (because it is subscribing to many
multicast groups whose combined bandwidth is momentarily greater than
the bandwidth of the link to the switch). Are the messages destined for
that endpoint dropped at the switch, or is traffic to the entire
multicast group delayed?
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next prev parent reply other threads:[~2015-11-25 17:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-24 22:10 When does IB Multicast drop? Peter Chinetti
[not found] ` <5654E056.5050608-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-11-24 23:08 ` Anuj Kalia
[not found] ` <CADPSxAgifjbSP0qL5fvRt8G7-qgTY0YjdFuPnB9WKi7kkUw55Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-11-25 16:10 ` Christoph Lameter
[not found] ` <alpine.DEB.2.20.1511251007020.31676-wcBtFHqTun5QOdAKl3ChDw@public.gmane.org>
2015-11-25 17:10 ` Peter Chinetti [this message]
[not found] ` <5655EB96.2090600-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-11-25 17:23 ` Christoph Lameter
2015-11-25 16:34 ` Peter Chinetti
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