On Ubuntu 16.04, with Samsung 850 EVO SSD, is any post configuration needed?

fstrim supports the option --all on Ubuntu 16.04.

$ lsb_release -dirc
Distributor ID: Ubuntu
Description:    Ubuntu 16.04.1 LTS
Release:        16.04
Codename:       xenial

$ fstrim --help

Usage:
 fstrim [options] <mount point>

Discard unused blocks on a mounted filesystem.

Options:
 -a, --all           trim all mounted filesystems that are supported
 -o, --offset <num>  the offset in bytes to start discarding from
 -l, --length <num>  the number of bytes to discard
 -m, --minimum <num> the minimum extent length to discard
 -v, --verbose       print number of discarded bytes

 -h, --help     display this help and exit
 -V, --version  output version information and exit

For more details see fstrim(8).

By default, Ubuntu 16.04 mounts all file systems with relatime. This works much better than noatime while adding only a very small number of write operations.

Do not mess with the I/O scheduler.

For peace of mind, you can use smartctl (install it with sudo apt-get install smartmontools if needed) from time to time to check on Life_Curve_Status, SSD_Life_Left, and Lifetime_Writes_GiB:

$ sudo smartctl --all /dev/sda
...
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME      FLAG    VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
...
194 Temperature_Celsius 0x0022  047   063   000    Old_age   Always       -       47 (Min/Max 21/63)
...
230 Life_Curve_Status   0x0013  100   100   000    Pre-fail  Always       -       100
231 SSD_Life_Left       0x0013  100   100   010    Pre-fail  Always       -       0
...
241 Lifetime_Writes_GiB 0x0032  000   000   000    Old_age   Always       -       388
...

(Life_Curve_Status and SSD_Life_Left have values in percentage points: you will want to replace the SSD when they decrease below 20% or 10%. If you can, make your terminal 132 columns before running smartctl.)

Finally, please remember that the 850 EVO is a high-quality expensive SSD from a reputable manufacturer. It is resilient and will last a long time, probably longer than any spinning disc. The only thing you can do which Samsung admits that it would help is to overprovision it a little, that is, when partitioning leave about 5% of unpartitioned space. (This will let the internal remapping / garbage collection algorithms work more efficiently; it you decide to do it then do it only when the SSD is new or after a full-disc trim or a security erase so that the overprovisioned space consists entirely of blocks known to be not in use.)