tcp troughput weirdness

Noritoshi Demizu demizu at dd.iij4u.or.jp
Tue Jul 12 09:53:49 GMT 2005


> combining
> 	sysctl net.inet.tcp.sendspace=131072
> and
> 	sysctl net.inet.tcp.inflight.enable=0
>
> did the trick!

Congratulations!  But I wonder why the throughput of FreeBSD=>Linux
was almost equal to that of Linux=>FreeBSD.  If the settings above
improves the throughput of FreeBSD=>FreeBSD, the throughput of
FreeBSD=>Linux would also be improved with them.  Is it improved?

> now can someone remind me what inflight does?

In my understanding, it tries to estimate bandwidth-delay product and
tries to avoid injecting too much data segments into networks.
So, if it underestimates bandwidth-delay product, throughtput may be
reduced.

Regards,
Noritoshi Demizu


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