my @k1 = keys(%hash1);
my @k2 = keys(%hash2);
# do they have the same number of elements?
if (@k1 != @k2) { # they're different...
}

# are the keys the same?
if (join($; , sort(@k1))
   ne join($; , sort(@k2))) { #they're different
}

# are the values the same?
if (join($; , @hash1{@k1})
   ne join($; , @hash2{@k1})) { #they're different
}