Realtime kernels can guarantee a certain response time to a process. For example the process has to read each 10ms the values from an control system. In realtime you can assure that no value is dropped.
If you don't operate some kind of manufactoring control system, you simple don't need it.
The overall system performance may be better if the kernel has not to guarantee every process a time slice in a period. (Better I/O utilization, lower process switch overhead etc etc)
To sum up: Realtime does not increase the throughput of a system.
Like Sergey "Shnatsel" Davidoff was quoted in that blog post, this package installs a script to run it as a service. The script automatically configures itself and the service starts up automatically. There is no further configuration needed. The service can be manually controlled via:
sudo service zramswap start|stop|status|restart|reload|force-reload
If you open the deb package with file roller you can see that only two files are installed:
/etc/init/zramswap.conf
/etc/init.d/zramswap
Along with some documentation files. The DEBIAN directory contains package meta data and commands to initialize the service. Thats all there is in the package. The corresponding devices are named after this scheme: /dev/zram[0-9]
Have you installed it via PPA? I recommend doing that.
Best Answer
Regarding 2., zswap does seem to decompress the pages on write-back, confirming @Cbhihe's comment.
mm/zswap.c, line 828:
So zswap is useful for situations where the compressed in-ram cache is likely to be forgotten soon before written back to disk. It is not for applications with large, long living heaps that will eventually need to be backed by the actual swap device.