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| author | Lukas Larsson <[email protected]> | 2014-09-11 18:26:26 +0200 |
|---|---|---|
| committer | Lukas Larsson <[email protected]> | 2016-02-02 10:45:21 +0100 |
| commit | eea5f896780e07f7ca76685061d01e7be5a7abaa (patch) | |
| tree | 7d4a852b20f2075637457052844865e1c56b1e21 /erts/preloaded | |
| parent | d76ee58c07f32dfc0652844ec2b513af2105ffa1 (diff) | |
| download | otp-eea5f896780e07f7ca76685061d01e7be5a7abaa.tar.gz otp-eea5f896780e07f7ca76685061d01e7be5a7abaa.tar.bz2 otp-eea5f896780e07f7ca76685061d01e7be5a7abaa.zip | |
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 'erts/preloaded')
| -rw-r--r-- | erts/preloaded/src/erlang.erl | 5 | ||||
| -rw-r--r-- | erts/preloaded/src/erts_internal.erl | 7 |
2 files changed, 10 insertions, 2 deletions
diff --git a/erts/preloaded/src/erlang.erl b/erts/preloaded/src/erlang.erl index bca366681d..6f56a81eec 100644 --- a/erts/preloaded/src/erlang.erl +++ b/erts/preloaded/src/erlang.erl @@ -71,7 +71,8 @@ | 'milli_seconds' | 'micro_seconds' | 'nano_seconds' - | 'native'. + | 'native' + | 'perf_counter'. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% Native code BIF stubs and their types @@ -1347,6 +1348,7 @@ convert_time_unit(Time, FromUnit, ToUnit) -> try FU = case FromUnit of native -> erts_internal:time_unit(); + perf_counter -> erts_internal:perf_counter_unit(); nano_seconds -> 1000*1000*1000; micro_seconds -> 1000*1000; milli_seconds -> 1000; @@ -1355,6 +1357,7 @@ convert_time_unit(Time, FromUnit, ToUnit) -> end, TU = case ToUnit of native -> erts_internal:time_unit(); + perf_counter -> erts_internal:perf_counter_unit(); nano_seconds -> 1000*1000*1000; micro_seconds -> 1000*1000; milli_seconds -> 1000; diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl index 84dedab930..c3a14d272d 100644 --- a/erts/preloaded/src/erts_internal.erl +++ b/erts/preloaded/src/erts_internal.erl @@ -45,7 +45,7 @@ -export([await_result/1, gather_io_bytes/2]). --export([time_unit/0]). +-export([time_unit/0, perf_counter_unit/0]). -export([is_system_process/1]). @@ -345,6 +345,11 @@ flush_monitor_messages(Ref, Multi, Res) when is_reference(Ref) -> time_unit() -> erlang:nif_error(undefined). +-spec erts_internal:perf_counter_unit() -> pos_integer(). + +perf_counter_unit() -> + erlang:nif_error(undefined). + -spec erts_internal:is_system_process(Pid) -> boolean() when Pid :: pid(). |