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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 /lib/kernel/src/os.erl | |
| 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 'lib/kernel/src/os.erl')
| -rw-r--r-- | lib/kernel/src/os.erl | 16 |
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(). |