On Sun May 10 10:58:55 PDT 2015, 0in...@gmail.com wrote: > >> however, after fixing things so the initial cwind isn't hosed, i get a > >> little better story: > > > > so, actually, i think this is the root cause. the intial cwind is misset > > for loopback. > > i but that the symptom folks will see is that /net/tcp/stats shows > > fragmentation when > > performance sucks. evidently there is a backoff bug in sources' tcp, too. > > What is your cwind change? >
the patch is here: /n/atom/patch/tcpmss note i applied a patch to nettest(8) to simulate a rpc-style protocol. i still ~500MB/s with my test machine simulating rpc-style transactions, or 15µs per 8k transaction. we're at least an order of magnitude off the performance mark for this. a similar test using pipe(2) shows a latency of 5.7µs (!) for a pipe-based rpc, which limits us to about 1.4 GB/s for 8k pipe-based ping-poing rpc. - erik
