Sync up with FreeBSD 10 version.

clientside/tmcc/freebsd9/loader.conf

@@ -12,21 +12,31 @@ beastie_disable="YES"
 hw.memtest.tests=0
 
 #
-# ixgbe driver will throttle back number of rx queues if not enough
-# nmbclusters; i.e., less than min(cores,8) * ports_on_card * ring_bufs,
-# which for the Utah d820s is 8 * 2 * 2048 == 32768. So we set nmbclusters
-# to that value here (and set the other nmb* values as the kernel would
-# based on that value). Note that it is not too much larger than the default
-# the kernel would calculate 25600 (which is based on "maxusers").
+# Some drivers, most notably the Intel 10Gb "ixgbe" driver and newer 1Gb
+# drivers, are very liberal with their mbuf allocation for RX buffers.
+# The ixgbe driver in particular wants to allocate up to 2048 buffers
+# per interface per CPU core (up to 8). On the Utah d820 nodes that is
+# 2048 * 4 * 8 == 65536 mbufs.
 #
-# These values will get re-adjusted in the Emulab startup scripts to a
-# more appropriate value based on the size of RAM and total number of
+# This can cause dhclient to fail when it fires up all interfaces at once
+# and the kernel runs out of mbufs.
+#
+# At Utah we avoid this by not dhcp'ing on the "ix" interfaces (see
+# /etc/rc.d/netif-emulab) because they are never the control net. But if
+# you have a 10Gb control net, or some other interface that allocates
+# excessive mbufs, you may need to try the following settings or something
+# even larger. Note that the relationship between the four values is the
+# same as what FreeBSD uses for the defaults; i.e., each value is half the
+# preceding value.
+#
+# Someday, these values will get re-adjusted in the Emulab startup scripts
+# to a more appropriate value based on the size of RAM and total number of
 # interfaces.
 #
-kern.ipc.nmbclusters=32768
-kern.ipc.nmbjumbop=16384
+kern.ipc.nmbclusters=65536
+kern.ipc.nmbjumbop=32768
+kern.ipc.nmbjumbo16=16384
 kern.ipc.nmbjumbo9=8192
-kern.ipc.nmbjumbo16=4096
 
 # force module path, our pxeboot can mess it up
 module_path="/boot/kernel;/boot/modules"