some weird performance result

Sungkwan Heo thuneh at
Sat Mar 11 08:25:46 CET 2006

Hi all,

I measured network I/O performance of native Linux-2.4 and
Fiasco-1.2+L4Linux-2.4 using the netperf benchmark.

The TCP streaming test results are following:

Recv Socket Size bytes: Linux = 87380, L4Linux = 87380
Send Socket Size bytes: Linux = 16384, L4Linux = 16384
Send Message Size bytes: Linux = 16384, L4Linux=16384
Elapsed Time secs: Linux = 10.002, L4Linux = 10.002
Throughput MBytes/s: Linux = 11.22, L4Linux = 11.206
Utilization Send local % S: Linux = 11.359, L4Linux = 4.35

The last 2 lines indicates the network I/O throughput and CPU utilization
for the network I/O.
One weird thing is the L4Linux CPU utilization. It spent much less CPU
cycles than the native Linux did.

In my humble opinion, it is normal case because the L4 Fiasco schedules the
L4Linux application (netperf) as a L4 process and L4Linux kernel doesn't
have correct CPU usage information of the application.

Is it correct?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the l4-hackers mailing list