The root cause is that #avx promisc section in "show run" as it uses ((6 * num.of NIC PF interfaces) + 2)  fork & exec to check the trust and vf promisc mode for all NIC PFs. Made changes to combine looking up of trust and vf promisc mode by using same child process output. Also used pf_port->driver attribute to check whether it is i40e port instead of using is_i40e_port() function. This reduces the num of fork & exec to ((1* num of NIC PF interfaces) + 1). 

Time taken for "sh run" previously was around 8s and after fix it is around 1s.

Time taken for "sh run" previously was around 8s and after fix it is around 1s.
AN(config)#sh run promisc
avx promisc configuration
promisc trust port3 2

promisc trust port8 2

promisc vf port2 1

promisc vf port2 2

promisc vf port8 2