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Justin Ross commented on QPID-3644: ----------------------------------- [~kpvdr], this one's pretty old. Can we close it? > qpid-perftest on c++ broker shows large consume rate drops at 64k message > size boundaries > ----------------------------------------------------------------------------------------- > > Key: QPID-3644 > URL: https://issues.apache.org/jira/browse/QPID-3644 > Project: Qpid > Issue Type: Bug > Components: C++ Broker, C++ Client > Affects Versions: 0.15 > Reporter: Kim van der Riet > > Using a 2-machine test connected with 10g private network, with one machine > containing the broker and the other the client, the following was observed: > Broker machine (20.0.10.43 on the 10g network): > ./qpidd --auth no > Client machine: > ./qpid-perftest -b 20.0.10.43 --count 20000 --size 65400 > (result: consume rate: 5437.45 transfers/sec) > ./qpid-perftest -b 20.0.10.43 --count 20000 --size 65500 > (result: consume rate: 696.628 transfers/sec) > which is a massive drop (to 13% of the initial rate) for a relatively small > change in message size of 100 bytes. > Again, around the 128k boundary: > ./qpid-perftest -b 20.0.10.43 --count 20000 --size 130900 > (result: consume rate: 546.144 transfers/sec) > ./qpid-perftest -b 20.0.10.43 --count 20000 --size 131100 > (result: consume rate: 177.607 transfers/sec) > which compounds the previous consume rate drop. > Further observations: > 1. If qpid-perftest is modified to print a single char every 100 consumes, > then it can be observed that performance is not linear, but starts out fast, > but slows down as the test progresses. Near the end of the test, the consume > rate starts to rapidly pick up again. > 2. Looking at broker trace logs, the consumed messages have a 40-byte header. > This means for these tests that the total message sizes are: > 65400 + 40 = 65440 > 65500 + 40 = 65540 > 130900 + 40 = 130940 > 131100 + 40 = 131140 > which straddle the 64k and 128k size boundaries. > 3. The drop in performance is not a step function, but as one draws closer to > (but still below) the boundary, the rate starts to rapidly deteriorate. eg > 65450 + 40 is below the 64k boundary, and has a result between the 65400 and > 65500 rates. Similarly for 131000 + 40, which is slightly below the 128k > boundary. -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@qpid.apache.org For additional commands, e-mail: dev-h...@qpid.apache.org