My times on x86-64 Linux are similar to yours, but on the Windows Subsystem for Linux (which emulates the Linux kernel) it's a different story:

  $ time python2 -c exit
  real    0m0.111s
  user    0m0.016s
  sys     0m0.078s

  $ time python3 -c exit
  real    0m0.063s
  user    0m0.016s
  sys     0m0.047s

Python 3 is consistently ~twice as fast. Both seem slower, but this is on a small laptop so the absolute measurements may not be comparable. This is on Creators Update.

That's better yet - thanks for sharing! Most of my Python processes run for weeks at a go, so startup time isn't that important to me as long as it's not glacial. But 40ms (on my system) or 22ms (on yours) is totally acceptable for interactive shell usage.

Thanks for including the syscall counts. I know they'd been working to reduce that, but I hadn't seen how much progress they'd made yet. Are most of those to malloc() and open()?

It absolutely is. Consider that that means that python takes 2-3 frames to start up. I'm not sure one should or could reasonably consider that "slow" for interactive use.

Mostly open, read, and fstat for python2:

     ~ strace python2 -c exit 2>&1 | sort | grep "^[a-z_]*[(]" | sed -e "s/^\([a-z_]*\)[(].*/\1/" | uniq -c | sort -rn | head -n 8
        199 open
         98 read
         94 fstat
         92 stat
         68 rt_sigaction
         63 close
         27 mmap
         16 mprotect

Mostly stat, rt_sigaction, and read for python3:

     ~ strace python3 -c exit 2>&1 | sort | grep "^[a-z_]*[(]" | sed -e "s/^\([a-z_]*\)[(].*/\1/" | uniq -c | sort -rn | head -n 8
         92 stat
         68 rt_sigaction
         57 read
         54 fstat
         35 open
         35 close
         28 mmap
         24 lseek

Some of this might be noise though, it's possible that it has something to do with the installed packages, not sure exactly.