Have you excluded the cost of establishing the TCP connection itself (something around 10 msec, depending on the setup)?
On Tue, Sep 29, 2015 at 8:49 AM, Ben Kloosterman <[email protected]> wrote: > "As can be seen, sender and receiver throughput's differ at the beginning of > the test. This seems to suggest that there is some kind of buffering > involved on the lower layers of the stack" > > Nagle is turned off but it looks like it keeps increasing some sort of > buffer in the tcp stack.. could also be OS / memory ( page allocation) / > Scheduling priority. > > Note in those 500 messages the sender was sending a lot more messages , than > the receiver was receiving so a buffer would be growing somewhere. > > Ben > > On Tue, Sep 29, 2015 at 4:35 PM, <[email protected]> wrote: >> >> Hi all, >> >> when sending many messages at once there is a known latency issue: The >> first 500 messages are sent with a high latency shown in the graph in the >> whitepaper http://zeromq.org/whitepapers:measuring-performance before it >> gets to very high speed messaging. >> >> The author summarizes: >> * For latency: ... the latency for first 500 messages is quite poor (up to >> 1,500 microseconds), however, afterwards it stabilises at approximately 150 >> microseconds, with occasional peaks up to 400 microseconds. >> * For throughput: This seems to suggest that there is some kind of >> buffering involved on the lower layers of the stack. >> >> In our scenario, we use a Dealer/Router connection, which is in fact like >> REQ/REP. >> >> Question: >> Why have the first 500 messages this latency issue? What is the reason for >> this and how could we solve this issue, because we require a high >> performance application even for the first messages. >> > > _______________________________________________ > zeromq-dev mailing list > [email protected] > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > _______________________________________________ zeromq-dev mailing list [email protected] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
