diff options
Diffstat (limited to 'erts/doc/src/erlang.xml')
| -rw-r--r-- | erts/doc/src/erlang.xml | 97 |
1 files changed, 86 insertions, 11 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 880c294c73..ba5f80a9c1 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -110,10 +110,17 @@ <note> <p>The value of the <c>native</c> time unit gives you more or less no information at all about the - quality of time values. It sets an upper bound for - the resolution as well as for the precision, but it - gives absolutely no information at all about the - accuracy.</p> + quality of time values. It sets a limit for + the + <seealso marker="time_correction#Time_Resolution">resolution</seealso> + as well as for the + <seealso marker="time_correction#Time_Precision">precision</seealso> + of time values, + but it gives absolutely no information at all about the + <seealso marker="time_correction#Time_Accuracy">accuracy</seealso> + of time values. The resolution of the <c>native</c> time + unit and the resolution of time values may differ + significantly.</p> </note> </item> @@ -6038,6 +6045,8 @@ ok <name name="system_info" arity="1" clause_i="62"/> <name name="system_info" arity="1" clause_i="63"/> <name name="system_info" arity="1" clause_i="64"/> + <name name="system_info" arity="1" clause_i="65"/> + <name name="system_info" arity="1" clause_i="66"/> <fsummary>Information about the system</fsummary> <desc> <p>Returns various information about the current system @@ -6449,20 +6458,33 @@ ok <c>Function</c>.</p></item> <tag><c>{resolution, OsMonotonicTimeResolution}</c></tag> - <item><p>Highest possible resolution of current - OS monotonic time source as parts per second. If - no resolution information can be retreived from - the OS, <c>OsMonotonicTimeResolution</c> will be + <item><p>Highest possible + <seealso marker="time_correction#Time_Resolution">resolution</seealso> + of current OS monotonic time source as parts per + second. If no resolution information can be retreived + from the OS, <c>OsMonotonicTimeResolution</c> will be set to the resolution of the time unit of <c>Function</c>s return value. That is, the actual resolution may be lower than <c>OsMonotonicTimeResolution</c>. Also note that the resolution does not say anything about the - accuracy, and that the precision might not align - with the resolution. You do, however, know that the - precision won't be higher than + <seealso marker="time_correction#Time_Accuracy">accuracy</seealso>, + and that the + <seealso marker="time_correction#Time_Precision">precision</seealso> + might not align with the resolution. You do, + however, know that the precision won't be + better than <c>OsMonotonicTimeResolution</c>.</p></item> + <tag><c>{extended, Extended}</c></tag> + <item><p><c>Extended</c> equals <c>yes</c> if + the range of time values has been extended; + otherwise, <c>Extended</c> equals <c>no</c>. The + range needs to be extended if <c>Function</c> + returns values that wrap fast. This typically + is the case when the return value is a 32-bit + value.</p></item> + <tag><c>{parallel, Parallel}</c></tag> <item><p><c>Parallel</c> equals <c>yes</c> if <c>Function</c> is called in parallel from multiple @@ -6476,6 +6498,59 @@ ok <seealso marker="#type_time_unit">time unit</seealso>.</p></item> </taglist> </item> + <tag><marker id="system_info_os_system_time_source"><c>os_system_time_source</c></marker></tag> + <item> + <p>Returns a list containing information about the source of + <seealso marker="erts:time_correction#OS_System_Time">OS + system time</seealso> that is used by the runtime system.</p> + <p>The list contains two-tuples with <c>Key</c>s + as first element, and <c>Value</c>s as second element. The + order if these tuples is undefined. Currently the following + tuples may be part of the list, but more tuples may be + introduced in the future:</p> + <taglist> + <tag><c>{function, Function}</c></tag> + <item><p><c>Function</c> is the name of the funcion + used.</p></item> + + <tag><c>{clock_id, ClockId}</c></tag> + <item><p>This tuple only exist if <c>Function</c> + can be used with different clocks. <c>ClockId</c> + corresponds to the clock identifer used when calling + <c>Function</c>.</p></item> + + <tag><c>{resolution, OsSystemTimeResolution}</c></tag> + <item><p>Highest possible + <seealso marker="time_correction#Time_Resolution">resolution</seealso> + of current OS system time source as parts per + second. If no resolution information can be retreived + from the OS, <c>OsSystemTimeResolution</c> will be + set to the resolution of the time unit of + <c>Function</c>s return value. That is, the actual + resolution may be lower than + <c>OsSystemTimeResolution</c>. Also note that + the resolution does not say anything about the + <seealso marker="time_correction#Time_Accuracy">accuracy</seealso>, + and that the + <seealso marker="time_correction#Time_Precision">precision</seealso> + might not align with the resolution. You do, + however, know that the precision won't be + better than + <c>OsSystemTimeResolution</c>.</p></item> + + <tag><c>{parallel, Parallel}</c></tag> + <item><p><c>Parallel</c> equals <c>yes</c> if + <c>Function</c> is called in parallel from multiple + threads. If it is not called in parallel, because + calls needs to be serialized, <c>Parallel</c> equals + <c>no</c>.</p></item> + + <tag><c>{time, OsSystemTime}</c></tag> + <item><p><c>OsSystemTime</c> equals current OS + system time in <c>native</c> + <seealso marker="#type_time_unit">time unit</seealso>.</p></item> + </taglist> + </item> <tag><marker id="system_info_port_parallelism"><c>port_parallelism</c></marker></tag> <item><p>Returns the default port parallelism scheduling hint used. For more information see the |