cbbackupmgr backup throughput is degraded in 6.5.0-4449 .
It appears to be due to one of the below memory related changes .
changed projects : kv_engine changed from 3e816d39c162d94ba643f14437af1fca697d17df to master
[+] 510acc6 Prepare Command Contexts for OoO [2/n]
[+] 8cdb2ce Update uses of AtomicDuration to new template platform changed from d2114be8ae6c40e72f890493cd4f3ead376d57a2 to master
[+] f42ec1e Allow memory order of AtomicDuration to be specified
replica doc comparison between two tests :