Experiment with GC options

[Boarders]

The user guide gives various options for runtime parameters particularly for tuning the garbage collector. We should experiment with changing the allocation area of the program to see if this makes a difference to our runtimes. This is done as follows: ./pcg +RTS -A1G -RTS The above command sets the allocation area to be 1GB. By default it is 1MB. We should see what settings seem to work best for a longer running example. The example here received a 3-6 times speed up from this change and so it is well worth looking into.

Similarly there are settings for the number of generations in the garbage collector. This can be changed as follows: ./pcg +RTS -G4 -RTS By default this is set at 2 and it is recommended in the user guide to not exceed 4. When we upgrade to GHC 8.10 we can also experiment with the new concurrent garbage collector which can be ran by compiling with threaded and using the run time options: ./pcg +RTS -xn -RTS