Re: UDP buffer sizes

[mlelstv%serpens.de@localhost (Michael van Elst)]

janicetr%posteo.de@localhost writes:

>sysctl -w kern.mbuf.nmbclusters=524288
>sysctl: kern.mbuf.nmbclusters: Invalid argument

>Maybe I hit a hard limit?

Limit is a quarter of kernel memory which is usually limited to a quarter
of physical memory (depends on the architecture). You are asking for
a Gigabyte and would need >16GB RAM.

As for UDP buffers, there is a global limit for all types of
socket buffers: kern.sbmax. The default is 256kB.

So if you want to bump UDP buffers to 4MB, kern.sbmax must be at least
as large. You also do not need to set net.inet.udp.*space, these are
the default sizes, but in your case the program sets the value.

nmbclusters is the space where all socket buffers are allocated from.
Even with one UDP socket buffer of 4MB the default should be enough,
otherwise increase it carefully. Each nmbcluster is 2kB, 

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."