You might try setting proxy.config.http.server_tcp_init_cwnd to something like 10.
Brian On Fri, Sep 5, 2014 at 3:51 PM, Fabien Duranti <[email protected]> wrote: > Hello, > > I am running a proof of concept with ATS 4.2.2 in reverse proxy mode to > improve user experience when accessing a web application over an high > latency link ( 255ms RTT ) > > The setup is the following : > > client -> ATS1 --- High latency link --- > ATS2 -> origin_server > > all connections have SSL. > > Everything behaves as expected when client requests are small, response > times when connections are established pretty much correspond to RTT + > origin response time + the negligible ATS processing time. > However, when requests are bigger than something around 3000bytes (POSTs > typically), reponse times are looking more like 2x RTT + origin response > time. > Running a network capture showed that when ATS1 sends a big request, there > are on the wire 2x 1500bytes packets sent, then wait for ATS2's ACK, then > another small packet to send the remaining of the request. That wait for > the ACK pretty much makes response times mutltipled by 2. > I immediately thought about the TCP tunning of the operating system > (RHEL6) could be wrong but running the exact same request with curl on ATS1 > wouldn't show that. on the wire we would rather see two fragmented packets > of 2650bytes + 800bytes and the response from ATS 2 comming shortly after > the RTT. > > Is there any misconfiguration in ATS that would explain this ? I tried > proxy.config.ssl.max_record_size = 0 then 1000, then 4000 but didn't see > any difference > > Thanks ! > > -- > Fabien Duranti >
