Eventing: Throughput regressed

Seeing multiple throughput tests regressed 

http://showfast.sc.couchbase.com/#/timeline/Linux/eventing/thr/Function#throughput50M_fun_bktop_eventing_rebalance_1s_1c_themis_eventing_rebalance 

Test job: 

http://perf.jenkins.couchbase.com/job/themis/17478/console 

cbmonitor: http://cbmonitor.sc.couchbase.com/reports/html/?snapshot=themis_711-3113_execute_handler_a4a7&snapshot=themis_711-3097_execute_handler_4545 

change log: http://changelog.build.couchbase.com/?product=couchbase-server&fromVersion=7.1.1&fromBuild=3097&toVersion=7.1.1&toBuild=3113&f_cbas=off&f_cbft=off&f_cbftx=off&f_cbgt=off&f_eventing=on&f_go_json=off&f_gometa=off&f_goxdcr=off&f_indexing=off&f_n1fty=off&f_ns_server=off&f_query=off&f_testrunner=off&f_tlm=off&f_vbmap=off 

It looks like the culprit build is  7.1.0-3099 , it has listen to multiple collection changes