[Freeswitch-users] High syscall percentage on Centos 7

Hi! Has anybody faced with high system calls on Centos 7 while running FreeSwitch? We have migrated from FS 1.2.23 on Centos 5.11 to FS 1.6.2 on Centos 7 and faced with very high syscall (up to 60% CPU time) rate under moderate load (300 CPS, 1500 simultaneous calls). We also faced the same issue on Centos 6.7 and Debian 8.2 with FS 1.6.2 on the same hardware. On Centos 5.11 with the same load and h/w we had no more than 10% syscalls CPU time. We have already tried nohz=off kernel option and it didn't solve the problem. What should we change in our environment to achieve the same performance level as it was on Centos 5.11?