Increase send/receive buffers to 7MiB

[bt90]

Fixes #4426

[bt90]

We also need to update the relevant section of the wiki.

non-BSD

sysctl -w net.core.rmem_max=7340032
sysctl -w net.core.wmem_max=7340032

BSD

sysctl -w kern.ipc.maxsockbuf=8441037

kern.ipc.maxsockbuf==8441037

[marten-seemann]

We also need to update the relevant section of the wiki.

non-BSD

sysctl -w net.core.rmem_max=7340032
sysctl -w net.core.wmem_max=7340032

BSD

sysctl -w kern.ipc.maxsockbuf=8441037

kern.ipc.maxsockbuf==8441037

Thanks. Updated on the new (unreleased) docs page.

[bt90]

@marten-seemann I just had a look at the updated wiki entry. Is there a reason why you use 7500000 instead of 7340032 for non-BSD? The defaults and most examples I could find online used values based on KiB/MiB instead of KB/MB.
No idea if this has any side effects or is just an aesthetic thing, though.