Vlad Yasevich wrote:
Doug Graham wrote:
Hi Vlad,
I'm probably just being stupid, but I can't figure out which version of
output.c your patch
is supposed to be applied against. Is it supposed to be applied on top
of any of the other
patches that Wei or I provided, or does it replace them all?
The main reason I ask is that as far as I can tell, your patch doesn't
change the original
mysterious condition for bundling a SACK, which was "if (asoc->a_rwnd >
asoc->rwnd)".
Well, I took your patch verbatum for that code. These two would apply on
top of that.
You can see the final code here:
http://git.kernel.org/?p=linux/kernel/git/vxy/lksctp-dev.git;a=shortlog;h=net-next
You can fetch from it like this:
# git fetch git://git.kernel.org/pub/scm/linux/kernel/git/vxy/lksctp-dev.git \
refs/heads/net-next:refs/heads/<name that branch here>
That will dump the net-next branch into a local branch that you named (can be
any new name).
Sorry, haven't had a lot of time to play with this until now. The
behaviour for
small unfragmented message looks fine, but if the message has to be
fragmented,
things don't look so good. I'm ping-ponging a 1500 byte message around:
client
sends 1500 bytes, server reads that and replies with the same message,
client
reads the reply then sleeps 2 seconds before doing it all over again. I
see no
piggybacking happening at all. A typical cycle looks like:
12 2.007226 10.0.0.248 10.0.0.249 SCTP DATA (1452 bytes data)
13 2.007268 10.0.0.248 10.0.0.249 SCTP DATA (48 bytes data)
14 2.007313 10.0.0.249 10.0.0.248 SCTP SACK
15 2.007390 10.0.0.249 10.0.0.248 SCTP SACK
16 2.007542 10.0.0.249 10.0.0.248 SCTP DATA
17 2.007567 10.0.0.249 10.0.0.248 SCTP DATA
18 2.007615 10.0.0.248 10.0.0.249 SCTP SACK
19 2.007661 10.0.0.248 10.0.0.249 SCTP SACK
Those back-to-back SACKs look wasteful too. One should have done the job,
although I suppose I can't be sure that SACKs aren't crossing DATA
on the wire. But the real mystery is why the SACKs were
sent immediately after the DATA was received. Looks like delayed SACKs
might be broken, although they are working for unfragmented messages.
--Doug
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