Auditd errors on busy hosts when rolling over log files

[Burn Alting]

Hi,

I have some quite busy hosts, that emit the following errors when I
request the audit log file is rolled over (via a kill -s USR1
auditdpid).

  Error receiving audit netlink packet(No buffer space available)
  Error sending signal_info request (No buffer space available)

>From reading earlier posts (circa 2009) it would appear my options are

a. Increase backlog buffer (currently 32768)
b. Increase priority_boost (currently 4)
c. Reduce the number of log files (currently 9)

Does anyone have a feel for which of the above should offer the best
return?

Are their other configuration parameters I could adjust (aside from
changing my ruleset in audit.rules)?

Thanks in advance

Burn