Solaris 8, samba 2.2.8a, high smbd CPU

[M.Maclaren at bath.ac.uk]

Servers: Solaris 8, kernel patch 108528-19, serving ~150 clients.
Samba  : 2.2.8a, built via:
 ./configure \
    --prefix=/opt/packages/samba/2.2.8a \
    --with-krb4=/opt/kerberosIV
Clients: many & varied

Problem: some smbd processes develop high CPU usage

In these cases, smbd logging shows repeated api_DosPrintQGetInfo: uLevel=2
client calls - as if the client is not getting an answer it appreciates.
  - in the cases I've investigated, the queues have been empty,
    and it isn't always the same queue.

smbd trussing shows many fcntl(14, F_SETLKW64, 0xFFBEF108) calls -
I believe because this is what is expected when smbd is
generating a response for DosPrintQGetInfo (scanning printing.tdb)
 - there are 148 printers available from these servers.

Printing setup is:

  use client driver = yes
  disable spoolss = yes
  printing = sysv
  printcap name = /opt/packages/samba/lib/smb.printcap
  load printers = yes
  lpq cache time = 60

Any ideas?
Martin