"ntpdate -q clock.redhat.com" takes almost 3.5 times longer in RHEL 7 than in RHEL 6

Issue

• ntpdate -q <some ntp server> command on RHEL 7 systems takes 7-8 seconds versus less than 4 seconds in RHEL 6

• On Red Hat Enterprise Linux 6:

  # ntpq --version
  ntpq 4.2.6p5                                                                                                                                                                                                                                  
  ntpq 4.2.6p5@1.2349-o Mon Dec 18 14:03:58 UTC 2017 (1) 
  # time ntpdate -u -q -p 2 clock.redhat.com
  server 10.5.26.10, stratum 1, offset 0.002779, delay 0.07281
  server 10.11.160.238, stratum 1, offset 0.002903, delay 0.02704
  server 10.16.255.1, stratum 1, offset 0.003301, delay 0.04623
  server 10.5.27.10, stratum 2, offset 0.002761, delay 0.07288
   3 Sep 00:27:02 ntpdate[17655]: adjust time server 10.11.160.238 offset 0.002903 sec
  
  real    0m0.799s  <<<<<<<
  user    0m0.000s
  sys 0m0.002s
  

• On Red Hat Enterprise Linux 7:

  # ntpq --version
  ntpq 4.2.6p5
  # time ntpdate -u -q -p 2 clock.redhat.com
  server 10.11.160.238, stratum 1, offset -0.000219, delay 0.02773
  server 10.16.255.1, stratum 1, offset 0.000375, delay 0.04633
  server 10.5.27.10, stratum 2, offset -0.000113, delay 0.07291
  server 10.5.26.10, stratum 1, offset 0.000068, delay 0.07382
   3 Sep 12:38:20 ntpdate[16786]: adjust time server 10.11.160.238 offset -0.000219 sec
  
  real    0m2.754s  <<<<<<<
  user    0m0.001s
  sys 0m0.003s