Interrupts in L4Linux

Julian Stecklina js at ...14...
Sat Mar 23 02:19:49 CET 2013


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.


Norman Feske <norman.feske at ...1...> wrote:

>Hi Ivan,
>> I've done test for nic_bridge, and I've updated page with results
>thanks for posting the results. One thing left me wondering: In the
>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.
>Dr.-Ing. Norman Feske
>Genode Labs
> ·
>Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden
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Sent from Kaiten Mail. Please excuse my brevity.
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