File 0719-Fix-unstable-tests-process_SUITE-no_priority_inversi.patch of Package erlang

From 91b25395276b2cb2467087133b57fbac795fde97 Mon Sep 17 00:00:00 2001
From: Rickard Green <rickard@erlang.org>
Date: Thu, 4 Jul 2019 18:05:44 +0200
Subject: [PATCH 1/3] Fix unstable tests
 process_SUITE:no_priority_inversion{,2}

Sometimes processes have not had the time to spread
from one scheduler. Force spread by using the undocumented
'scheduler' option.
---
 erts/emulator/test/process_SUITE.erl | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/erts/emulator/test/process_SUITE.erl b/erts/emulator/test/process_SUITE.erl
index a8bcfac84d..cafab983ad 100644
--- a/erts/emulator/test/process_SUITE.erl
+++ b/erts/emulator/test/process_SUITE.erl
@@ -2394,14 +2394,20 @@ garb_other_running(Config) when is_list(Config) ->
 
 no_priority_inversion(Config) when is_list(Config) ->
     Prio = process_flag(priority, max),
-    HTLs = lists:map(fun (_) ->
+    Master = self(),
+    Executing = make_ref(),
+    HTLs = lists:map(fun (Sched) ->
 			     spawn_opt(fun () ->
+                                               Master ! {self(), Executing},
 					       tok_loop()
 				       end,
-				       [{priority, high}, monitor, link])
+				       [{priority, high},
+                                        {scheduler, Sched},
+                                        monitor,
+                                        link])
 		     end,
-		     lists:seq(1, 2*erlang:system_info(schedulers))),
-    receive after 500 -> ok end,
+		     lists:seq(1, erlang:system_info(schedulers_online))),
+    lists:foreach(fun ({P, _}) -> receive {P,Executing} -> ok end end, HTLs),
     LTL = spawn_opt(fun () ->
 			    tok_loop()
 		    end,
@@ -2423,14 +2429,19 @@ no_priority_inversion(Config) when is_list(Config) ->
 
 no_priority_inversion2(Config) when is_list(Config) ->
     Prio = process_flag(priority, max),
-    MTLs = lists:map(fun (_) ->
+    Master = self(),
+    Executing = make_ref(),
+    MTLs = lists:map(fun (Sched) ->
 			     spawn_opt(fun () ->
+                                               Master ! {self(), Executing},
 					       tok_loop()
 				       end,
-				       [{priority, max}, monitor, link])
+				       [{priority, max},
+                                        {scheduler, Sched},
+                                        monitor, link])
 		     end,
-		     lists:seq(1, 2*erlang:system_info(schedulers))),
-    receive after 2000 -> ok end,
+		     lists:seq(1, erlang:system_info(schedulers_online))),
+    lists:foreach(fun ({P, _}) -> receive {P,Executing} -> ok end end, MTLs),
     {PL, ML} = spawn_opt(fun () ->
 			       tok_loop()
 		       end,
-- 
2.16.4