Latency and Throughput test regressed with plasma and plasma DGM

Build: 7.1.1-3166

Seeing multiple regressions in plasma test with 10K indexes, also 10% RR compression test also regressed

Latency 

http://showfast.sc.couchbase.com/#/timeline/Linux/secondary/lat/Plasma#secondary_scan50M_plasma_10k_indexes_1s_1000c_10kops_90th_hemera 

Latency DGM

http://showfast.sc.couchbase.com/#/timeline/Linux/secondary/lat/PlasmaDGM#secondary_scan100M_plasma_10k_indexes_10_70_nonoverlapping_20res_1s_1000c_90th_hemera

Throughput 

http://showfast.sc.couchbase.com/#/timeline/Linux/secondary/thr/Plasma#secondary_scan50M_plasma_10k_indexes_1s_1000c_10kops_thr_hemera 

Throughput DGM 

http://showfast.sc.couchbase.com/#/timeline/Linux/secondary/thr/PlasmaDGM#secondary_scan100M_plasma_10k_indexes_10_70_nonoverlapping_20res_1s_1000c_thr_hemera 

Compression 

http://showfast.sc.couchbase.com/#/timeline/Linux/secondary/thr/Compression#secondary_compression_10res_80_20_thr_hemera 

Change logs : http://changelog.build.couchbase.com/?product=couchbase-server&fromVersion=7.1.1&fromBuild=3135&toVersion=7.1.1&toBuild=3166&f_asterixdb=off&f_backup=off&f_cbas-core=off&f_cbauth=off&f_cbbs=off&f_cbft=off&f_cbftx=off&f_cbgt=off&f_cbsummary=off&f_eventing=off&f_eventing-ee=off&f_goxdcr=off&f_indexing=on&f_kv_engine=off&f_n1fty=off&f_ns_server=off&f_plasma=on&f_query=off&f_testrunner=off&f_tlm=off&f_vbmap=off

Logs from :  Secondary Scan Throughput (scanps) 1 bucket x 100M x 1KB, 2K KV ops/sec, 10000 indexes, 10/70 non-overlapping mutations and scans, 20% Resident, Plasma, s=1 c=1000

Throughput 

17,860 (71.1-3166) vs 61,037.4 (71.1-3135)

Test job : http://perf.jenkins.couchbase.com/job/hemera/5213/console 

GSI logs: https://s3-us-west-2.amazonaws.com/perf-artifacts/jenkins-hemera-5213/cen-s705.perf.couchbase.com.zip 

cbmonitor: http://cbmonitor.sc.couchbase.com/reports/html/?snapshot=hemera_711-3135_apply_scanworkload_42e0&snapshot=hemera_711-3166_apply_scanworkload_a4c1