From eea5f896780e07f7ca76685061d01e7be5a7abaa Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Thu, 11 Sep 2014 18:26:26 +0200 Subject: 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 --- lib/kernel/src/os.erl | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'lib/kernel/src') 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(). -- cgit v1.2.3