[erlang-questions] Gen_UDP Packet Loss

[Michael.K.Schmidt@REDACTED]

One other thing to keep in mind is that the ethernet switch will have a big
impact on your test.  If a packet collision occurs inside the switch (when
a packet is being transferred from one port queue to another), it is can be
hard dropped.  The sending NIC thinks the packet was transmitted, so no
attempt is made to retransmit on the wire.  Higher-End switches handle this
better (more queue space,etc), but it can still be an issue.


Lee Sylvester <lee.sylvester@REDACTED> wrote on 07/30/2014 03:12:47 PM:

> Lee Sylvester <lee.sylvester@REDACTED>
> 07/30/2014 03:12 PM
>
> To
>
> Michael.K.Schmidt@REDACTED,
>
> cc
>
> "Erlang Users' List" <erlang-questions@REDACTED>, erlang-
> questions-bounces@REDACTED, Max Lapshin <max.lapshin@REDACTED>
>
> Subject
>
> Re: [erlang-questions] Gen_UDP Packet Loss
>
> Thanks, Mike.  I tried that, but it hasn’t made any changes :-(
>
> Lee
>
>
> On 30 Jul 2014, at 21:07, Michael.K.Schmidt@REDACTED wrote:
>
> >
> > Don't you want to adjust the UDP (not TCP) settings? something like
> >
> > sysctl -w net.inet.udp.recvspace=1048576
> >
> > I don't know if this still applies, but there is a writeup here on how
to
> > increase maxsockbuf:
> > http://lists.apple.com/archives/darwin-kernel/2012/Apr/msg00042.html
> >
> > # tell the system to use more than the
> > # default 32768 mbufclusters via the ncl boot arg
> > nvram boot-args="ncl=131072"
> >
> > (reboot)
> >
> > sysctl -w kern.ipc.maxsockbuf=16777216
> > sysctl -w net.inet.udp.recvspace=8388608
> >
> >
> > Hope that helps,
> > Mike
> >
> >
> > erlang-questions-bounces@REDACTED wrote on 07/30/2014 02:24:56 PM:
> >
> >> Lee Sylvester <lee.sylvester@REDACTED>
> >> Sent by: erlang-questions-bounces@REDACTED
> >>
> >> 07/30/2014 02:24 PM
> >>
> >> To
> >>
> >> Max Lapshin <max.lapshin@REDACTED>,
> >>
> >> cc
> >>
> >> "Erlang Users' List" <erlang-questions@REDACTED>
> >>
> >> Subject
> >>
> >> Re: [erlang-questions] Gen_UDP Packet Loss
> >>
> >> Okay, so I’m updating them using
> >>
> >> sysctl -w kern.ipc.maxsockbuf=16777216
> >> sysctl -w net.inet.tcp.sendspace=1048576
> >> sysctl -w net.inet.tcp.recvspace=1048576
> >>
> >> Apparently that produces the same result.  16777216 is reported as
> >> too large for the maxsockbuf, though.  I’m on a Macbook Pro with
> >> 8Gb.  :rolleyes:
> >>
> >> Lee
> >>
> >> On 30 Jul 2014, at 20:06, Max Lapshin <max.lapshin@REDACTED> wrote:
> >>
> >> I've spent lot of time to make capturing of 600 mbit/s of udp
> >> traffic without loss.
> >>
> >> Don't specify buffer size in erlang, use system variables.
> >>
> >>
> >>
> >>
> >> sysctl -w net.core.rmem_max=1048576
> >> sysctl -w net.core.rmem_default=1048576
> >> sysctl -w net.ipv4.udp_mem="8388608 12582912 16777216"
> >>
> >>
> >> ______________________________________________________________________
> >> This email has been scanned by the Symantec Email Security.cloud
service.
> >> ______________________________________________________________________
> >> _______________________________________________
> >> erlang-questions mailing list
> >> erlang-questions@REDACTED
> >> http://erlang.org/mailman/listinfo/erlang-questions
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> ______________________________________________________________________