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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/doc/src/os.xml | |
| 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/doc/src/os.xml')
| -rw-r--r-- | lib/kernel/doc/src/os.xml | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/lib/kernel/doc/src/os.xml b/lib/kernel/doc/src/os.xml index 682d4a2eac..165160a909 100644 --- a/lib/kernel/doc/src/os.xml +++ b/lib/kernel/doc/src/os.xml @@ -37,6 +37,7 @@ use these functions can be of help in enabling a program to run on most platforms.</p> </description> + <funcs> <func> <name name="cmd" arity="1"/> @@ -210,6 +211,30 @@ format_utc_timestamp() -> </desc> </func> <func> + <name name="perf_counter" arity="0"/> + <fsummary>Returns a performance counter</fsummary> + <desc> + <p>Returns the current performance counter value in <c>perf_counter</c> + <seealso marker="erts:erlang#type_time_unit">time unit</seealso>. + This is a highly optimized call that might not be traceable. + </p> + </desc> + </func> + <func> + <name name="perf_counter" arity="1"/> + <fsummary>Returns a performance counter</fsummary> + <desc><p>Returns a performance counter that can be used as a very fast and + high resolution timestamp. This counter is read directly from the hardware or operating + system with the same guarantees. This means that two consecutive calls + to the function are not guaranteed to be monotonic, though it most likely will be. + The performance counter till be converted to the resolution passed as an argument.</p> + <pre>1> <input>T1 = os:perf_counter(1000),receive after 10000 -> ok end,T2 = os:perf_counter(1000).</input> +176525861 +2> <input>T2 - T1.</input> +10004</pre> + </desc> + </func> + <func> <name name="type" arity="0"/> <fsummary>Return the OS family and, in some cases, OS name of the current operating system</fsummary> <desc> |