$ perl -MDevel::Size=total_size -wE'my%h=(test1=>[1..3],test2=>[4..6]);say"$_ -> ",total_size$h{$_}for keys%h'
test1 -> 160
test2 -> 160
$ perl -wE'my%h=(test1=>[1..3],test2=>[4..6]);say"$_ -> ",scalar@{$h{$_}}for keys%h'
test2 -> 3
test1 -> 3