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authorLukas Larsson <[email protected]>2014-09-12 16:38:00 +0200
committerLukas Larsson <[email protected]>2016-02-02 10:45:21 +0100
commit664ed2a6fd2b324bb6b56db3d3eca853cfda8f61 (patch)
tree286743a4b1f794948329961e7f5879b5f54f54a5 /erts/preloaded
parenteea5f896780e07f7ca76685061d01e7be5a7abaa (diff)
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erts: Add microstate accounting
Microstate accounting is a way to track which state the different threads within ERTS are in. The main usage area is to pin point performance bottlenecks by checking which states the threads are in and then from there figuring out why and where to optimize. Since checking whether microstate accounting is on or off is relatively expensive if done in a short loop only a few of the states are enabled by default and more states can be enabled through configure. I've done some benchmarking and the overhead with it turned off is not noticible and with it on it is a fraction of a percent. If you enable the extra states, depending on the benchmark, the ovehead when turned off is about 1% and when turned on somewhere inbetween 5-15%. OTP-12345
Diffstat (limited to 'erts/preloaded')
-rw-r--r--erts/preloaded/src/erlang.erl13
-rw-r--r--erts/preloaded/src/erts_internal.erl28
2 files changed, 41 insertions, 0 deletions
diff --git a/erts/preloaded/src/erlang.erl b/erts/preloaded/src/erlang.erl
index 6f56a81eec..ab51cf385c 100644
--- a/erts/preloaded/src/erlang.erl
+++ b/erts/preloaded/src/erlang.erl
@@ -2217,6 +2217,16 @@ spawn_opt(_Tuple) ->
(io) -> {{input, Input}, {output, Output}} when
Input :: non_neg_integer(),
Output :: non_neg_integer();
+ (microstate_accounting) -> [MSAcc_Thread] | undefined when
+ MSAcc_Thread :: #{ type => MSAcc_Thread_Type,
+ id => MSAcc_Thread_Id,
+ counters => MSAcc_Counters},
+ MSAcc_Thread_Type :: scheduler | async | aux,
+ MSAcc_Thread_Id :: non_neg_integer(),
+ MSAcc_Counters :: #{ MSAcc_Thread_State => non_neg_integer() },
+ MSAcc_Thread_State :: alloc | aux | bif | busy_wait | check_io |
+ emulator | ets | gc | gc_fullsweep | nif |
+ other | port | send | sleep | timers;
(reductions) -> {Total_Reductions,
Reductions_Since_Last_Call} when
Total_Reductions :: non_neg_integer(),
@@ -2271,6 +2281,9 @@ subtract(_,_) ->
(fullsweep_after, Number) -> OldNumber when
Number :: non_neg_integer(),
OldNumber :: non_neg_integer();
+ (microstate_accounting, Action) -> OldState when
+ Action :: true | false | reset,
+ OldState :: true | false;
(min_heap_size, MinHeapSize) -> OldMinHeapSize when
MinHeapSize :: non_neg_integer(),
OldMinHeapSize :: non_neg_integer();
diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl
index c3a14d272d..a15355bb10 100644
--- a/erts/preloaded/src/erts_internal.erl
+++ b/erts/preloaded/src/erts_internal.erl
@@ -49,6 +49,9 @@
-export([is_system_process/1]).
+-export([await_microstate_accounting_modifications/3,
+ gather_microstate_accounting_result/2]).
+
%% Auto import name clash
-export([check_process_code/2]).
@@ -355,3 +358,28 @@ perf_counter_unit() ->
is_system_process(_Pid) ->
erlang:nif_error(undefined).
+
+-spec await_microstate_accounting_modifications(Ref, Result, Threads) -> boolean() when
+ Ref :: reference(),
+ Result :: boolean(),
+ Threads :: pos_integer().
+
+await_microstate_accounting_modifications(Ref, Result, Threads) ->
+ _ = microstate_accounting(Ref,Threads),
+ Result.
+
+-spec gather_microstate_accounting_result(Ref, Threads) -> [#{}] when
+ Ref :: reference(),
+ Threads :: pos_integer().
+
+gather_microstate_accounting_result(Ref, Threads) ->
+ microstate_accounting(Ref, Threads).
+
+microstate_accounting(_Ref, 0) ->
+ [];
+microstate_accounting(Ref, Threads) ->
+ receive
+ Ref -> microstate_accounting(Ref, Threads - 1);
+ {Ref, Res} ->
+ [Res | microstate_accounting(Ref, Threads - 1)]
+ end.