If parameters specifies a single GC parameter, the value of that parameter is returned. Otherwise values is an alist containing every GC parameter, together with its current value.
See set-gc-parameters for a full description of these parameters.
With keyword argument, of one of the parameters, the corresponding value is returned.
CL-USER 1 > (get-gc-parameters :minimum-overflow)
500000
CL-USER 2 > (pprint (get-gc-parameters t))
((:ENLARGE-BY-SEGMENTS . 10)
(:MINIMUM-FOR-PROMOTE . 1000)
(:MAXIMUM-OVERFLOW . 1000000)
(:MINIMUM-OVERFLOW . 500000)
(:MINIMUM-BUFFER-SIZE . 200)
(:NEW-GENERATION-SIZE . 262144)
(:PROMOTE-MAX-BUFFER . 100000)
(:PROMOTE-MIN-BUFFER . 200)
(:MAXIMUM-BUFFER-SIZE . 131072)
(:MINIMUM-FOR-SWEEP . 8000)
(:BIG-OBJECT . 131072))