From 573a5abd9d6b1668b49376b489b187780c7125c7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20H=C3=B6gberg?= Date: Tue, 27 Mar 2018 13:14:40 +0200 Subject: erts: Rewrite memory instrumentation This commit replaces the old memory instrumentation with a new implementation that scans carriers instead of wrapping erts_alloc/erts_free. The old implementation could not extract information without halting the emulator, had considerable runtime overhead, and the memory maps it produced were noisy and lacked critical information. Since the new implementation walks through existing data structures there's no longer a need to start the emulator with special flags to get information about carrier utilization/fragmentation. Memory fragmentation is also easier to diagnose as it's presented on a per-carrier basis which eliminates the need to account for "holes" between mmap segments. To help track allocations, each allocation can now be tagged with what it is and who allocated it at the cost of one extra word per allocation. This is controlled on a per-allocator basis with the +Matags option, and is enabled by default for binary_alloc and driver_alloc (which is also used by NIFs). --- erts/preloaded/src/erlang.erl | 55 ++++-------------------------------- erts/preloaded/src/erts_internal.erl | 23 +++++++++++++++ 2 files changed, 29 insertions(+), 49 deletions(-) (limited to 'erts/preloaded/src') diff --git a/erts/preloaded/src/erlang.erl b/erts/preloaded/src/erlang.erl index bffa59338e..9c2f8ef0ae 100644 --- a/erts/preloaded/src/erlang.erl +++ b/erts/preloaded/src/erlang.erl @@ -3552,11 +3552,9 @@ max(A, _) -> A. %% -type memory_type() :: 'total' | 'processes' | 'processes_used' | 'system' - | 'atom' | 'atom_used' | 'binary' | 'code' | 'ets' - | 'low' | 'maximum'. + | 'atom' | 'atom_used' | 'binary' | 'code' | 'ets'. -define(CARRIER_ALLOCS, [mseg_alloc]). --define(LOW_ALLOCS, [ll_low_alloc, std_low_alloc]). -define(ALL_NEEDED_ALLOCS, (erlang:system_info(alloc_util_allocators) -- ?CARRIER_ALLOCS)). @@ -3568,9 +3566,7 @@ max(A, _) -> A. atom_used = 0, binary = 0, code = 0, - ets = 0, - low = 0, - maximum = 0}). + ets = 0}). -spec erlang:memory() -> [{Type, Size}] when Type :: memory_type(), @@ -3580,14 +3576,6 @@ memory() -> notsup -> erlang:error(notsup); Mem -> - InstrTail = case Mem#memory.maximum of - 0 -> []; - _ -> [{maximum, Mem#memory.maximum}] - end, - Tail = case Mem#memory.low of - 0 -> InstrTail; - _ -> [{low, Mem#memory.low} | InstrTail] - end, [{total, Mem#memory.total}, {processes, Mem#memory.processes}, {processes_used, Mem#memory.processes_used}, @@ -3596,7 +3584,7 @@ memory() -> {atom_used, Mem#memory.atom_used}, {binary, Mem#memory.binary}, {code, Mem#memory.code}, - {ets, Mem#memory.ets} | Tail] + {ets, Mem#memory.ets}] end. -spec erlang:memory(Type :: memory_type()) -> non_neg_integer(); @@ -3684,16 +3672,6 @@ need_mem_info(binary) -> {false, [binary_alloc], true, false}; need_mem_info(ets) -> {true, [ets_alloc], true, false}; -need_mem_info(low) -> - LowAllocs = ?LOW_ALLOCS -- ?CARRIER_ALLOCS, - {_, _, FeatureList, _} = erlang:system_info(allocator), - AlcUAllocs = case LowAllocs -- FeatureList of - [] -> LowAllocs; - _ -> [] - end, - {false, AlcUAllocs, true, true}; -need_mem_info(maximum) -> - {true, [], true, true}; need_mem_info(_) -> {false, [], false, true}. @@ -3706,8 +3684,6 @@ get_memval(atom_used, #memory{atom_used = V}) -> V; get_memval(binary, #memory{binary = V}) -> V; get_memval(code, #memory{code = V}) -> V; get_memval(ets, #memory{ets = V}) -> V; -get_memval(low, #memory{low = V}) -> V; -get_memval(maximum, #memory{maximum = V}) -> V; get_memval(_, #memory{}) -> 0. memory_is_supported() -> @@ -3762,16 +3738,6 @@ fix_proc([_ | Rest], Acc) -> fix_proc([], Acc) -> Acc. -is_low_alloc(_A, []) -> - false; -is_low_alloc(A, [A|_As]) -> - true; -is_low_alloc(A, [_A|As]) -> - is_low_alloc(A, As). - -is_low_alloc(A) -> - is_low_alloc(A, ?LOW_ALLOCS). - au_mem_data(notsup, _) -> notsup; au_mem_data(_, [{_, false} | _]) -> @@ -3824,16 +3790,11 @@ au_mem_data(#memory{total = Tot, Rest) end; au_mem_data(#memory{total = Tot, - system = Sys, - low = Low} = Mem, - [{A, _, Data} | Rest]) -> + system = Sys} = Mem, + [{_, _, Data} | Rest]) -> Sz = blocks_size(Data, 0), au_mem_data(Mem#memory{total = Tot+Sz, - system = Sys+Sz, - low = case is_low_alloc(A) of - true -> Low+Sz; - false -> Low - end}, + system = Sys+Sz}, Rest); au_mem_data(EMD, []) -> EMD. @@ -3854,10 +3815,6 @@ receive_emd(Ref, EMD, N) -> receive_emd(Ref) -> receive_emd(Ref, #memory{}, erlang:system_info(schedulers)). -aa_mem_data(#memory{} = Mem, - [{maximum, Max} | Rest]) -> - aa_mem_data(Mem#memory{maximum = Max}, - Rest); aa_mem_data(#memory{} = Mem, [{total, Tot} | Rest]) -> aa_mem_data(Mem#memory{total = Tot, diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl index da5c9c68ed..79169b7d23 100644 --- a/erts/preloaded/src/erts_internal.erl +++ b/erts/preloaded/src/erts_internal.erl @@ -80,6 +80,8 @@ -export([is_process_alive/1, is_process_alive/2]). +-export([gather_alloc_histograms/1, gather_carrier_info/1]). + %% %% Await result of send to port %% @@ -621,3 +623,24 @@ is_process_alive(Pid) -> Res end. +-spec gather_alloc_histograms({Type, SchedId, HistWidth, HistStart, Ref}) -> MsgCount when + Type :: atom(), + SchedId :: non_neg_integer(), + HistWidth :: non_neg_integer(), + HistStart :: non_neg_integer(), + Ref :: reference(), + MsgCount :: non_neg_integer(). + +gather_alloc_histograms(_) -> + erlang:nif_error(undef). + +-spec gather_carrier_info({Type, SchedId, HistWidth, HistStart, Ref}) -> MsgCount when + Type :: atom(), + SchedId :: non_neg_integer(), + HistWidth :: non_neg_integer(), + HistStart :: non_neg_integer(), + Ref :: reference(), + MsgCount :: non_neg_integer(). + +gather_carrier_info(_) -> + erlang:nif_error(undef). -- cgit v1.2.3