DragonFly kernel List (threaded) for 2005-07
Re: MAXSAVEDBLOCKS in netinet/tcp_sack.c
: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.
This is one for Jeff to consider when he gets back as well. I do
like the idea of having a sysctl.
But I will note that the saved blocks are in fact the number of
discontiguous segment ranges, not single segments. That should make it
fairly independant of the bandwidth delay product on a real network.
If you use dummynet to inject random errors... well, that isn't really
a characteristic of a real network. I still believe that there are
certain situations where one might need to bump the number up, which
is why I like the sysctl idea. I'm not sure the default needs to be