From 6992261d258f2fc0b25ddf99ebcbf66ae02f5df8 Mon Sep 17 00:00:00 2001 From: Dan Gudmundsson Date: Wed, 25 Jan 2012 15:44:16 +0100 Subject: emulator: Document and test scheduler_wall_time --- erts/doc/src/erlang.xml | 26 ++++++++- erts/emulator/test/statistics_SUITE.erl | 98 ++++++++++++++++++++++++++++----- 2 files changed, 109 insertions(+), 15 deletions(-) (limited to 'erts') diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index a603d5c2b8..f2b95678b9 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -4,7 +4,7 @@
- 19962011 + 19962012 Ericsson AB. All Rights Reserved. @@ -4933,6 +4933,21 @@ true threads in the Erlang run-time system and may therefore be greater than the wall-clock time.

+ scheduler_wall_time + +

Returns + [{Scheduler_Id, Scheduler_Worked_Time, Scheduler_Total_Time}], time lapses are since the + the system flag scheduler_wall_time + was set to true. + Returns undefined if the system flag + scheduler_wall_time is set to false. +

+

The list of scheduler information is unsorted and may come in different order + between calls. The time unit is undefined and may be changed and should only be used + to calculate relative utilization. +

+ + wall_clock

Returns @@ -5305,6 +5320,14 @@ true flags.

+ erlang:system_flag(scheduler_wall_time, Boolean) + +

Turns on/off scheduler wall time measurements.

+

For more information see, + erlang:statistics(scheduler_wall_time). +

+ + erlang:system_flag(schedulers_online, SchedulersOnline)

Sets the amount of schedulers online. Valid range is @@ -5316,6 +5339,7 @@ true erlang:system_info(schedulers_online).

+ erlang:system_flag(trace_control_word, TCW)

Sets the value of the node's trace control word to diff --git a/erts/emulator/test/statistics_SUITE.erl b/erts/emulator/test/statistics_SUITE.erl index 0392312a6f..a93dd309c1 100644 --- a/erts/emulator/test/statistics_SUITE.erl +++ b/erts/emulator/test/statistics_SUITE.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 1997-2011. All Rights Reserved. +%% Copyright Ericsson AB 1997-2012. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in @@ -29,6 +29,7 @@ runtime_zero_diff/1, runtime_update/1, runtime_diff/1, run_queue_one/1, + scheduler_wall_time/1, reductions/1, reductions_big/1, garbage_collection/1, io/1, badarg/1]). @@ -51,8 +52,8 @@ suite() -> [{ct_hooks,[ts_install_cth]}]. all() -> [{group, wall_clock}, {group, runtime}, reductions, - reductions_big, {group, run_queue}, garbage_collection, - io, badarg]. + reductions_big, {group, run_queue}, scheduler_wall_time, + garbage_collection, io, badarg]. groups() -> [{wall_clock, [], @@ -266,11 +267,10 @@ run_queue_one(Config) when is_list(Config) -> run_queue_one_test(Config) when is_list(Config) -> - ?line Hog = spawn_link(?MODULE, hog, [self()]), + ?line _Hog = spawn_link(?MODULE, hog, [self()]), ?line receive - hog_started -> - Hog ! go - end, + hog_started -> ok + end, ?line receive after 100 -> ok end, % Give hog a head start. ?line case statistics(run_queue) of N when N >= 1 -> ok; @@ -280,18 +280,88 @@ run_queue_one_test(Config) when is_list(Config) -> %% CPU-bound process, going at low priority. It will always be ready %% to run. - + hog(Pid) -> ?line process_flag(priority, low), ?line Pid ! hog_started, - ?line receive - go -> hog_iter(0) + ?line Mon = erlang:monitor(process, Pid), + ?line hog_iter(0, Mon). + +hog_iter(N, Mon) when N > 0 -> + receive + {'DOWN', Mon, _, _, _} -> ok + after 0 -> + ?line hog_iter(N-1, Mon) + end; +hog_iter(0, Mon) -> + ?line hog_iter(10000, Mon). + +%%% Tests of statistics(scheduler_wall_time). + +scheduler_wall_time(doc) -> + "Tests that statistics(scheduler_wall_time) works as intended"; +scheduler_wall_time(Config) when is_list(Config) -> + %% Should return undefined if system_flag is not turned on yet + undefined = statistics(scheduler_wall_time), + %% Turn on statistics + false = erlang:system_flag(scheduler_wall_time, true), + try + Schedulers = erlang:system_info(schedulers_online), + %% Let testserver and everyone else finish their work + timer:sleep(500), + %% Empty load + EmptyLoad = get_load(), + {false, _} = {lists:any(fun(Load) -> Load > 50 end, EmptyLoad),EmptyLoad}, + MeMySelfAndI = self(), + StartHog = fun() -> + Pid = spawn(?MODULE, hog, [self()]), + receive hog_started -> MeMySelfAndI ! go end, + Pid + end, + P1 = StartHog(), + %% Max on one, the other schedulers empty (hopefully) + %% Be generous the process can jump between schedulers + %% which is ok and we don't want the test to fail for wrong reasons + _L1 = [S1Load|EmptyScheds1] = get_load(), + {true,_} = {S1Load > 50,S1Load}, + {false,_} = {lists:any(fun(Load) -> Load > 50 end, EmptyScheds1),EmptyScheds1}, + {true,_} = {lists:sum(EmptyScheds1) < 60,EmptyScheds1}, + + %% 50% load + HalfHogs = [StartHog() || _ <- lists:seq(1, (Schedulers-1) div 2)], + HalfLoad = lists:sum(get_load()) div Schedulers, + if Schedulers < 2, HalfLoad > 80 -> ok; %% Ok only one scheduler online and one hog + %% We want roughly 50% load + HalfLoad > 40, HalfLoad < 60 -> ok; + true -> exit({halfload, HalfLoad}) + end, + + %% 100% load + LastHogs = [StartHog() || _ <- lists:seq(1, Schedulers div 2)], + FullScheds = get_load(), + {false,_} = {lists:any(fun(Load) -> Load < 80 end, FullScheds),FullScheds}, + FullLoad = lists:sum(FullScheds) div Schedulers, + if FullLoad > 90 -> ok; + true -> exit({fullload, FullLoad}) + end, + + [exit(Pid, kill) || Pid <- [P1|HalfHogs++LastHogs]], + AfterLoad = get_load(), + {false,_} = {lists:any(fun(Load) -> Load > 5 end, AfterLoad),AfterLoad}, + true = erlang:system_flag(scheduler_wall_time, false) + after + erlang:system_flag(scheduler_wall_time, false) end. -hog_iter(N) when N > 0 -> - ?line hog_iter(N-1); -hog_iter(0) -> - ?line hog_iter(10000). +get_load() -> + Start = erlang:statistics(scheduler_wall_time), + timer:sleep(500), + End = erlang:statistics(scheduler_wall_time), + lists:reverse(lists:sort(load_percentage(lists:sort(Start),lists:sort(End)))). + +load_percentage([{Id, WN, TN}|Ss], [{Id, WP, TP}|Ps]) -> + [100*(WN-WP) div (TN-TP)|load_percentage(Ss, Ps)]; +load_percentage([], []) -> []. garbage_collection(doc) -> -- cgit v1.2.3