OCE driver on Freebsd 10.0-Current

[Venkata Duvvuru]

Hi,
I'm running iperf on Emulex's OCE network adapter in Freebsd-10-current. At heavy traffic (iperf with ~10 connections), iperf is hanging. The same driver is working on all other Freebsd versions.
top -HS shows the below information.
PID USERNAME   PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
   11 root       155 ki31     0K   128K CPU4    4 146:36 100.00% idle{idle: cpu4}
   12 root       -60    -     0K   688K CPU6    6  52:38 100.00% intr{swi4: clock}
   11 root       155 ki31     0K   128K CPU2    2 148:42 99.66% idle{idle: cpu2}
   11 root       155 ki31     0K   128K CPU7    7 149:24 99.27% idle{idle: cpu7}
   11 root       155 ki31     0K   128K RUN     0 148:00 99.27% idle{idle: cpu0}
   11 root       155 ki31     0K   128K CPU1    1 149:44 99.17% idle{idle: cpu1}
   11 root       155 ki31     0K   128K CPU5    5 148:46 99.17% idle{idle: cpu5}
   11 root       155 ki31     0K   128K CPU3    3  96:57 89.06% idle{idle: cpu3}
   11 root       155 ki31     0K   128K RUN     6 149:11 13.87% idle{idle: cpu6}

One interesting thing I observed is that intr is taking 100% on CPU6 when iperf hangs, while iperf is running fine, the intr WCPU percentage is very low. What does this below line mean? Why intr is 100% on CPU6??
12 root       -60    -     0K   688K CPU6    6  52:38 100.00% intr{swi4: clock}

/Venkat.