We got the same issue for php client. In our situation, we have 5 aerospike servers and 10 php servers. On each php server, we have 500~1000 php-fpm processes.
After deployed on php server with php-client-3.4.3, the aerospike servers got very high CPU usages (1200% above on 24 cores machine), even there are very few active write requests.
we have enabled the persistent connection flag.