Currently there's a globally set limit for datagrams which can be queued in an AF_UNIX/SOCK_DGRAM socket, and it is really low:
$ cat /proc/sys/net/unix/max_dgram_qlen
In order to increase concurrency at boot we'd really like to bump this up for some sockets (such as syslog sockets), but only for these very specific sockets. While we currently can bump the socket buffers per-socket there's no way to specify how many datagrams to queue. So even if we have huge socket buffers we still only can queue 10 dgrams in them, and that's mighty little... :-(
you need to take this upstream to firstname.lastname@example.org
We don't have manpower to implement every RFE we get filed, and we're not going to introduce new APIs that aren't upstream anyway.