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-rw-r--r--lib/kernel/test/os_SUITE.erl47
1 files changed, 27 insertions, 20 deletions
diff --git a/lib/kernel/test/os_SUITE.erl b/lib/kernel/test/os_SUITE.erl
index 3cbb75a633..1233e362f2 100644
--- a/lib/kernel/test/os_SUITE.erl
+++ b/lib/kernel/test/os_SUITE.erl
@@ -319,31 +319,38 @@ perf_counter_api(_Config) ->
true = is_integer(os:perf_counter()),
true = os:perf_counter() > 0,
- T1 = os:perf_counter(),
+ Conv = fun(T1, T2) ->
+ erlang:convert_time_unit(T2 - T1, perf_counter, nanosecond)
+ end,
+
+ do_perf_counter_test([], Conv, 120000000, 80000000),
+ do_perf_counter_test([1000], fun(T1, T2) -> T2 - T1 end, 120, 80).
+
+do_perf_counter_test(CntArgs, Conv, Upper, Lower) ->
+ %% We run the test multiple times to try to get a somewhat
+ %% stable value... what does this test? That the
+ %% calculate_perf_counter_unit in sys_time.c works somewhat ok.
+ do_perf_counter_test(CntArgs, Conv, Upper, Lower, 10).
+
+do_perf_counter_test(CntArgs, _Conv, Upper, Lower, 0) ->
+ ct:fail("perf_counter_test ~p ~p ~p",[CntArgs, Upper, Lower]);
+do_perf_counter_test(CntArgs, Conv, Upper, Lower, Iters) ->
+
+ T1 = apply(os, perf_counter, CntArgs),
timer:sleep(100),
- T2 = os:perf_counter(),
- TsDiff = erlang:convert_time_unit(T2 - T1, perf_counter, nanosecond),
- ct:pal("T1: ~p~n"
+ T2 = apply(os, perf_counter, CntArgs),
+ TsDiff = Conv(T1, T2),
+ ct:log("T1: ~p~n"
"T2: ~p~n"
"TsDiff: ~p~n",
[T1,T2,TsDiff]),
- %% We allow a 15% diff
- true = TsDiff < 115000000,
- true = TsDiff > 85000000,
-
- T1Ms = os:perf_counter(1000),
- timer:sleep(100),
- T2Ms = os:perf_counter(1000),
- MsDiff = T2Ms - T1Ms,
- ct:pal("T1Ms: ~p~n"
- "T2Ms: ~p~n"
- "MsDiff: ~p~n",
- [T1Ms,T2Ms,MsDiff]),
-
- %% We allow a 15% diff
- true = MsDiff < 115,
- true = MsDiff > 85.
+ if
+ TsDiff < Upper, TsDiff > Lower ->
+ ok;
+ true ->
+ do_perf_counter_test(CntArgs, Conv, Upper, Lower, Iters-1)
+ end.
%% Util functions