[cfarm-users] Max UDP dgram size on M1 machine (gcc304)

Segher Boessenkool segher at kernel.crashing.org
Thu Mar 25 00:45:02 CET 2021

On Wed, Mar 24, 2021 at 08:39:10AM -0700, Kaz Kylheku via cfarm-users wrote:
> On Mac OS, there are, by default, bizarre restrictions on IP datagram 
> sizes
> in the protocol stack.
> Would it be possible to put this configuration into effect:
>    sysctl -w net.inet.udp.maxdgram=65535

The default is not a restriction, but meant for good performance:
it is 9216, which is the maximum MTU for any supported network

If you use something bigger, you get way worse performance (up to and
including 0 bits per second) if the network is a bit busy, drops some
packets, etc.


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