my %grp_advise = (
               "grp1" => "normal,random,sequential",
               "grp2" => "willneed,dontneed,free",
               "grp3" => "access_lwp,access_many,access_default"
              );

foreach my $grp (keys %grp_advise) {
        my $advise_value = $grp_advise{$grp};
        print "$grp ===> $advise_value\n";

}