MAXSAVEDBLOCKS in netinet/tcp_sack.c

[Noritoshi Demizu <demizu@xxxxxxxxxxxxxx>]

I'm running TCP experiences between DragonFlyBSD and FreeBSD.
In my experiences, both send buffer and receive buffer are 4MBytes.
And RTT is set to 20ms using Dummynet.

In that case, since bandwidth delay product is large, MAXSAVEDBLOCKS
in netinet/tcp_sack.c is too small to use DragonFlyBSD as a sender.
I need to change the value from 8 to 128 for my experiences.

So, I'd like to suggest to change the value of MAXSAVEDBLOCKS to
a larger value.  I also would like to suggest to introduce a new
sysctl variable to control the maximum number of saved blocks.

Thank you.

Regards,
Noritoshi Demizu