Ivan,
you can easily see whether Linux has suboptimal TCP configuration by opening multiple TCP connections at once and check if this increases total throughput. In this case TCP windows don't grow to the required size. Norman already mentioned it, but a simple way to fix this is to give Linux lots of RAM (1GB does not hurt). I would expect your (native) setup to always max out the 1Gb link bandwidth. You should always plot CPU utilization as well.
Julian
Hi Ivan,I've done test for nic_bridge, and I've updated page with results
http://ksyslabs.org/doku.php?id=genode_network_perfomance#nic_bridge_test
thanks for posting the results. One thing left me wondering: In the last
scenario, the roles of both L4Linux instances look entirely symmetric.
How can it be that the benchmark produces different results when
swapping the roles of both instances? Are both instances configured
identically? In particular, do they have the same amount of RAM
configured? I'm asking because we observed that the TCP parameters of
the Linux TCP/IP stack depend on the memory available to Linux .
Apart from that, your measurement seems to support my presumption that
the driver is the bottleneck. Even with two Linux instances running and
the overhead introduced by the indirection via nic_bridge, the
throughput stays in the same order as native Linux.
Do you share my interpretation? If so, it would be worthwhile to focus
the investigation on the driver.
Cheers
Norman