rpcbind is getting stuck - Freebsd 9.2-STABLE

[Daniel Braniss]

Hi,
we have serveral hosts running 9.2-stable, without major issues, except
this host:
	CPU: Intel(R) Xeon(R) CPU E5-2640 0 @ 2.50GHz (2500.05-MHz K8-class CPU)
	...
	real memory  = 51539607552 (49152 MB)
	avail memory = 49344880640 (47058 MB)
	Event timer "LAPIC" quality 600
	ACPI APIC Table: <DELL   PE_SC3  >
	FreeBSD/SMP: Multiprocessor System Detected: 24 CPUs
	FreeBSD/SMP: 2 package(s) x 6 core(s) x 2 SMT threads

it is a nfs server from zfs , very few hosts access it (about 3 web servers),
it's connected via 10G, and very often rpcbind gets stuck on select,

any help on how to debug/fix this is more than welcome.

danny