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authorLukas Larsson <[email protected]>2014-09-11 18:26:26 +0200
committerLukas Larsson <[email protected]>2016-02-02 10:45:21 +0100
commiteea5f896780e07f7ca76685061d01e7be5a7abaa (patch)
tree7d4a852b20f2075637457052844865e1c56b1e21 /lib/kernel/src
parentd76ee58c07f32dfc0652844ec2b513af2105ffa1 (diff)
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erts, kernel: Add os:perf_counter function
The perf_counter is a very very cheap and high resolution timer that can be used to timestamp system events. It does not have monoticity guarantees, but should on most OS's expose a monotonous time. A special instruction has been created for this counter to further speed up fetching it. OTP-12908
Diffstat (limited to 'lib/kernel/src')
-rw-r--r--lib/kernel/src/os.erl16
1 files changed, 15 insertions, 1 deletions
diff --git a/lib/kernel/src/os.erl b/lib/kernel/src/os.erl
index 0022959c11..4947088635 100644
--- a/lib/kernel/src/os.erl
+++ b/lib/kernel/src/os.erl
@@ -27,7 +27,9 @@
%%% BIFs
--export([getenv/0, getenv/1, getenv/2, getpid/0, putenv/2, system_time/0, system_time/1,
+-export([getenv/0, getenv/1, getenv/2, getpid/0,
+ perf_counter/0, perf_counter/1,
+ putenv/2, system_time/0, system_time/1,
timestamp/0, unsetenv/1]).
-spec getenv() -> [string()].
@@ -60,6 +62,18 @@ getenv(VarName, DefaultValue) ->
getpid() ->
erlang:nif_error(undef).
+-spec perf_counter() -> Counter when
+ Counter :: integer().
+
+perf_counter() ->
+ erlang:nif_error(undef).
+
+-spec perf_counter(Unit) -> integer() when
+ Unit :: erlang:time_unit().
+
+perf_counter(Unit) ->
+ erlang:convert_time_unit(os:perf_counter(), perf_counter, Unit).
+
-spec putenv(VarName, Value) -> true when
VarName :: string(),
Value :: string().