diff options
Diffstat (limited to 'erts/emulator/test/nif_SUITE.erl')
| -rw-r--r-- | erts/emulator/test/nif_SUITE.erl | 159 |
1 files changed, 157 insertions, 2 deletions
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl index 693db42e58..8ad11d3bf3 100644 --- a/erts/emulator/test/nif_SUITE.erl +++ b/erts/emulator/test/nif_SUITE.erl @@ -56,7 +56,10 @@ nif_is_process_alive/1, nif_is_port_alive/1, nif_term_to_binary/1, nif_binary_to_term/1, nif_port_command/1, - nif_snprintf/1 + nif_snprintf/1, + nif_internal_hash/1, + nif_internal_hash_salted/1, + nif_phash2/1 ]). -export([many_args_100/100]). @@ -90,7 +93,10 @@ all() -> nif_is_process_alive, nif_is_port_alive, nif_term_to_binary, nif_binary_to_term, nif_port_command, - nif_snprintf]. + nif_snprintf, + nif_internal_hash, + nif_internal_hash_salted, + nif_phash2]. groups() -> [{G, [], api_repeaters()} || G <- api_groups()] @@ -2610,6 +2616,154 @@ nif_snprintf(Config) -> <<"{{hello,world,-33},",0>> = format_term_nif(20,{{hello,world, -33}, 3.14, self()}), ok. +nif_internal_hash(Config) -> + ensure_lib_loaded(Config), + HashValueBitSize = nif_hash_result_bitsize(internal), + Terms = unique([random_term() || _ <- lists:seq(1, 5000)]), + HashValues = [hash_nif(internal, Term, 0) || Term <- Terms], + test_bit_distribution_fitness(HashValues, HashValueBitSize, 0.05). + +nif_internal_hash_salted(Config) -> + ensure_lib_loaded(Config), + test_salted_nif_hash(internal). + +nif_phash2(Config) -> + ensure_lib_loaded(Config), + HashValueBitSize = nif_hash_result_bitsize(phash2), + Terms = unique([random_term() || _ <- lists:seq(1, 5000)]), + HashValues = + lists:map( + fun (Term) -> + HashValue = erlang:phash2(Term), + Salt = random_uint32(), % phash2 should ignore salt + NifHashValue = hash_nif(phash2, Term, Salt), + (HashValue =:= NifHashValue + orelse ct:fail("Expected: ~p\nActual: ~p", + [HashValue, NifHashValue])), + HashValue + end, + Terms), + test_bit_distribution_fitness(HashValues, HashValueBitSize, 0.05). + +test_salted_nif_hash(HashType) -> + HashValueBitSize = nif_hash_result_bitsize(HashType), + Terms = unique([random_term() || _ <- lists:seq(1, 5000)]), + Salts = unique([random_uint32() || _ <- lists:seq(1, 100)]), + {HashValuesPerSalt, HashValuesPerTerm} = + lists:mapfoldl( + fun (Salt, Acc) -> + {HashValues, NewAcc} = + lists:mapfoldl( + fun (Term, AccB) -> + HashValue = hash_nif(HashType, Term, Salt), + NewAccB = dict:append(Term, HashValue, AccB), + {HashValue, NewAccB} + end, + Acc, + Terms), + {{Salt, HashValues}, NewAcc} + end, + dict:new(), + Salts), + + % Test per-salt hash distribution of different terms + lists:foreach( + fun ({_Salt, HashValues}) -> + test_bit_distribution_fitness(HashValues, HashValueBitSize, 0.05) + end, + HashValuesPerSalt), + + % Test per-term hash distribution of different salts + dict:fold( + fun (_Term, HashValues, Acc) -> + % Be more tolerant of relative deviation, + % as there's fewer hash values here. + test_bit_distribution_fitness(HashValues, HashValueBitSize, 0.30), + Acc + end, + ok, + HashValuesPerTerm). + +test_bit_distribution_fitness(Integers, BitSize, MaxRelativeDeviation) -> + MaxInteger = (1 bsl BitSize) - 1, + OnesPerBit = + lists:foldl( + fun (Integer, Acc) when Integer >= 0, Integer =< MaxInteger -> + lists:foldl( + fun (BitIndex, AccB) -> + BitValue = (Integer band (1 bsl BitIndex)) bsr BitIndex, + orddict:update_counter(BitIndex, BitValue, AccB) + end, + Acc, + lists:seq(0, BitSize - 1)) + end, + orddict:new(), + Integers), + + ExpectedNrOfOnes = length(Integers) div 2, + FailureText = + orddict:fold( + fun (BitIndex, NrOfOnes, Acc) -> + RelativeDeviation = abs(NrOfOnes - ExpectedNrOfOnes) / length(Integers), + case RelativeDeviation >= MaxRelativeDeviation of + false -> Acc; + true -> + [Acc, + io_lib:format( + "Unreasonable deviation on number of set bits (i=~p): " + "expected ~p, got ~p (relative dev. ~.3f)~n", + [BitIndex, ExpectedNrOfOnes, NrOfOnes, RelativeDeviation])] + end + end, + [], + OnesPerBit), + + (FailureText =:= [] orelse ct:fail(FailureText)). + +nif_hash_result_bitsize(internal) -> 32; +nif_hash_result_bitsize(phash2) -> 27. + +unique(List) -> + lists:usort(List). + +random_uint32() -> + rand:uniform(1 bsl 32) - 1. + +random_term() -> + case rand:uniform(6) of + 1 -> rand:uniform(1 bsl 27) - 1; % small + 2 -> (1 bsl 27) + rand:uniform(1 bsl 128); % big + 3 -> random_sign() * (rand:uniform() * (1 bsl 53)); % float + 4 -> random_binary(); + 5 -> random_pid(); + 6 -> + Length = rand:uniform(10), + List = [random_term() || _ <- lists:seq(1, Length)], + case rand:uniform(2) of + 1 -> + List; + 2 -> + list_to_tuple(List) + end + end. + +random_sign() -> + case rand:uniform(2) of + 1 -> -1.0; + 2 -> 1.0 + end. + +random_binary() -> + list_to_binary(random_bytes(rand:uniform(32) - 1)). + +random_bytes(0) -> + []; +random_bytes(N) when N > 0 -> + [rand:uniform(256) - 1 | random_bytes(N - 1)]. + +random_pid() -> + Processes = erlang:processes(), + lists:nth(rand:uniform(length(Processes)), Processes). %% The NIFs: lib_version() -> undefined. @@ -2621,6 +2775,7 @@ type_test() -> ?nif_stub. tuple_2_list(_) -> ?nif_stub. is_identical(_,_) -> ?nif_stub. compare(_,_) -> ?nif_stub. +hash_nif(_Type, _Term, _Salt) -> ?nif_stub. many_args_100(_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_) -> ?nif_stub. clone_bin(_) -> ?nif_stub. make_sub_bin(_,_,_) -> ?nif_stub. |