LINUX (Linux mgnt 4.15.0-64-generic #73-Ubuntu SMP Thu Sep 12 13:16:13 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux)
2 vCPU
gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1) 

real    0m14.765s
user    0m11.089s
sys     0m3.623s

real    0m15.010s
user    0m11.199s
sys     0m3.754s

real    0m14.885s
user    0m11.322s
sys     0m3.520s

SMARTOS (SunOS sm01 5.11 joyent_20190925T185257Z i86pc i386 i86pc)
8 vCPU
gcc version 7.4.0 (GCC) 

real    0m33.641s
user    0m15.288s
sys     0m16.834s

real    0m32.935s
user    0m15.200s
sys     0m16.752s

real    0m33.848s
user    0m15.444s
sys     0m16.933s

DRAGONFLY BSD (DragonFly dfly99.sector.int 5.7-DEVELOPMENT DragonFly v5.7.0.598.g53b15d-DEVELOPMENT #6: Tue Oct  1 23:11:40 CEST 2019     antonioh@dfly99.sector.int:/usr/obj/home/antonioh/s/dragonfly/sys/X86_64_GENERIC  x86_64)
3 vCPU
gcc version 8.3 [DragonFly] Release/2019-02-22 

       14.63 real         8.97 user         5.64 sys

       14.79 real         9.23 user         5.54 sys

       14.97 real         9.35 user         5.60 sys

FREEBSD (FreeBSD fbsdx64.sector.int 12.0-RELEASE-p6 FreeBSD 12.0-RELEASE-p6 GENERIC  amd64)
4 vCPU

- FreeBSD clang version 6.0.1 (tags/RELEASE_601/final 335540) (based on LLVM 6.0.1)

       15.80 real         6.73 user         3.33 sys

       10.65 real         6.63 user         3.38 sys

       10.76 real         6.66 user         3.26 sys


- gcc version 7.4.0 (FreeBSD Ports Collection) 

       18.06 real        10.45 user         4.35 sys

       15.35 real        10.28 user         4.70 sys

       15.03 real         9.95 user         4.74 sys

NETBSD (NetBSD netbsd64.sector.int 8.99.45 NetBSD 8.99.45 (GENERIC) #0: Fri Jun 14 11:51:28 CEST 2019  root@netbsd64.sector.int:/usr/obj/sys/arch/amd64/compile/GENERIC amd64)
2 vCPU

gcc version 7.4.0 (nb3 20190319) 

vm.ubc_direct = 0

       20.85 real        12.50 user         6.27 sys

       21.04 real        12.49 user         6.07 sys

       21.32 real        12.06 user         6.56 sys

vm.ubc_direct = 1

       21.63 real        12.93 user         6.29 sys

       22.20 real        12.40 user         7.07 sys

       21.57 real        12.43 user         6.77 sys