Lua - Current time in milliseconds

Question

Is there a common way to get the current time in or with milliseconds   There is os time    but it only provides full seconds

User · Answer

You can use C function gettimeofday   http   www opengroup org onlinepubs 000095399 functions gettimeofday html  Here C library  ul time   function sec usec resides in  time  global table and returns seconds  useconds  Copy DLL to Lua folder  open it with require  ul time    http   depositfiles com files 3g2fx7dij

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If your environment is Windows and you have access to system commands  you can get time of centiseconds precision with io popen command   local handle   io popen  quot echo  time  quot   local result   handle read  quot  a quot   handle close    The result will hold string of hh mm ss cc format   with trailing line break   quot 19 56 53 90 n quot   Note  it s in local timesone  so you probably want to extract only the  cc part and combine it with epoch seconds from os time

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If your environment is Windows and you have access to system commands  you can get time of centiseconds precision with io popen command   local handle   io popen  quot echo  time  quot   local result   handle read  quot  a quot   handle close    The result will hold string of hh mm ss cc format   with trailing line break   quot 19 56 53 90 n quot   Note  it s in local timesone  so you probably want to extract only the  cc part and combine it with epoch seconds from os time

User · Answer

In standard C lua  no   You will have to settle for seconds  unless you are willing to modify the lua interpreter yourself to have os time use the resolution you want   That may be unacceptable  however  if you are writing code for other people to run on their own and not something like a web application where you have full control of the environment   Edit  another option is to write your own small DLL in C that extends lua with a new function that would give you the values you want  and require that dll be distributed with your code to whomever is going to be using it

User · Answer

Get current time in milliseconds   os time    os time   return sec    only   posix clock gettime clk   https   luaposix github io luaposix modules posix time html clock gettime  require posix  clock gettime 0  return sec  nsec   linux time h    man clock gettime        The IDs of the various system clocks  for POSIX 1b interval timers        define CLOCK REALTIME                  0  define CLOCK MONOTONIC                 1  define CLOCK PROCESS CPUTIME ID        2  define CLOCK THREAD CPUTIME ID         3  define CLOCK MONOTONIC RAW             4  define CLOCK REALTIME COARSE           5  define CLOCK MONOTONIC COARSE          6   socket gettime    http   w3 impa br  diego software luasocket socket html gettime  require socket  gettime   return sec xxx   as waqas says    compare  amp  test  get millisecond lua  local posix require posix  local socket require socket   for i 1 3 do     print  os time         print  posix clock gettime 0        print  socket gettime         print       posix nanosleep 0  1  -- sec  nsec end   output  lua get millisecond lua 1490186718 1490186718      268570540 1490186718 2686  1490186718 1490186718      268662191 1490186718 2687  1490186718 1490186718      268782765 1490186718 2688

User · Answer

You can use C function gettimeofday   http   www opengroup org onlinepubs 000095399 functions gettimeofday html  Here C library  ul time   function sec usec resides in  time  global table and returns seconds  useconds  Copy DLL to Lua folder  open it with require  ul time    http   depositfiles com files 3g2fx7dij

User · Answer

In standard C lua  no   You will have to settle for seconds  unless you are willing to modify the lua interpreter yourself to have os time use the resolution you want   That may be unacceptable  however  if you are writing code for other people to run on their own and not something like a web application where you have full control of the environment   Edit  another option is to write your own small DLL in C that extends lua with a new function that would give you the values you want  and require that dll be distributed with your code to whomever is going to be using it

User · Answer

in openresty there is a function ngx req start time   From the docs      Returns a floating-point number representing the timestamp  including milliseconds as the decimal part  when the current request was created

User · Answer

If you re using lua with nginx openresty you could use ngx now   which returns a float with millisecond precision

User · Answer

If you re using OpenResty then it provides for in-built millisecond time accuracy through the use of its ngx now   function  Although if you want fine grained millisecond accuracy then you may need to call ngx update time   first  Or if you want to go one step further     If you are using luajit enabled environment  such as OpenResty  then you can also use ffi to access C based time functions such as gettimeofday   e g   Note  The pcall check for the existence of struct timeval is only necessary if you re running it repeatedly e g  via content by lua file in OpenResty - without it you run into errors such as attempt to redefine  timeval    if pcall ffi typeof   struct timeval   then         -- check if already defined  else         -- undefined  let s define it          ffi cdef              typedef struct timeval                   long tv sec                  long tv usec               timeval           int gettimeofday struct timeval  t  void  tzp      end local gettimeofday struct   ffi new  struct timeval   local function gettimeofday           ffi C gettimeofday gettimeofday struct  nil          return tonumber gettimeofday struct tv sec    1000000   tonumber gettimeofday struct tv usec  end   Then the new lua gettimeofday   function can be called from lua to provide the clock time to microsecond level accuracy   Indeed  one could take a similar approaching using clock gettime   to obtain nanosecond accuracy

User · Answer

I use LuaSocket to get more precision   require  socket  print  Milliseconds       socket gettime   1000    This adds a dependency of course  but works fine for personal use  in benchmarking scripts for example

User · Answer

I use LuaSocket to get more precision   require  socket  print  Milliseconds       socket gettime   1000    This adds a dependency of course  but works fine for personal use  in benchmarking scripts for example

User · Answer

I use LuaSocket to get more precision   require  socket  print  Milliseconds       socket gettime   1000    This adds a dependency of course  but works fine for personal use  in benchmarking scripts for example

User · Answer

Kevlar is correct    An alternative to a custom DLL is Lua Alien

User · Answer

Kevlar is correct    An alternative to a custom DLL is Lua Alien

User · Answer

In standard C lua  no   You will have to settle for seconds  unless you are willing to modify the lua interpreter yourself to have os time use the resolution you want   That may be unacceptable  however  if you are writing code for other people to run on their own and not something like a web application where you have full control of the environment   Edit  another option is to write your own small DLL in C that extends lua with a new function that would give you the values you want  and require that dll be distributed with your code to whomever is going to be using it

User · Answer

If you want to benchmark  you can use os clock as shown by the doc   local x   os clock   local s   0 for i 1 100000 do s   s   i end print string format  elapsed time    2f n   os clock   - x

User · Answer

If you re using OpenResty then it provides for in-built millisecond time accuracy through the use of its ngx now   function  Although if you want fine grained millisecond accuracy then you may need to call ngx update time   first  Or if you want to go one step further     If you are using luajit enabled environment  such as OpenResty  then you can also use ffi to access C based time functions such as gettimeofday   e g   Note  The pcall check for the existence of struct timeval is only necessary if you re running it repeatedly e g  via content by lua file in OpenResty - without it you run into errors such as attempt to redefine  timeval    if pcall ffi typeof   struct timeval   then         -- check if already defined  else         -- undefined  let s define it          ffi cdef              typedef struct timeval                   long tv sec                  long tv usec               timeval           int gettimeofday struct timeval  t  void  tzp      end local gettimeofday struct   ffi new  struct timeval   local function gettimeofday           ffi C gettimeofday gettimeofday struct  nil          return tonumber gettimeofday struct tv sec    1000000   tonumber gettimeofday struct tv usec  end   Then the new lua gettimeofday   function can be called from lua to provide the clock time to microsecond level accuracy   Indeed  one could take a similar approaching using clock gettime   to obtain nanosecond accuracy

User · Answer

If you want to benchmark  you can use os clock as shown by the doc   local x   os clock   local s   0 for i 1 100000 do s   s   i end print string format  elapsed time    2f n   os clock   - x

User · Answer

in openresty there is a function ngx req start time   From the docs      Returns a floating-point number representing the timestamp  including milliseconds as the decimal part  when the current request was created

User · Answer

I made a suitable solution for lua on Windows  I basically did what Kevlar suggested  but with a shared library rather than a DLL  This has been tested using cygwin   I wrote some lua compatible C code  compiled it to a shared library   so file via gcc in cygwin   and then loaded it up in lua using package cpath and require     Wrote an adapter script for convenience  Here is all of the source   first the C code  HighResTimer c                                                                     HighResTimer c by Cody Duncan      compile with   gcc -o Timer so -shared HighResTimer c -llua5 1   compiled in cygwin after installing lua  cant remember if I       installed via setup or if I downloaded and compiled lua        probably the former                                                                    include  lt windows h gt   typedef unsigned   int64 u64  double mNanoSecondsPerCount    include  lua h   include  lualib h   include  lauxlib h    int prevInit   0  int currInit   0  u64 prevTime   0  u64 currTime   0  u64 FrequencyCountPerSec   LARGE INTEGER frequencyTemp  static int readHiResTimerFrequency lua State  L        QueryPerformanceFrequency  amp frequencyTemp       FrequencyCountPerSec   frequencyTemp QuadPart      lua pushnumber L  frequencyTemp QuadPart       return 1     LARGE INTEGER timerTemp  static int storeTime lua State  L        QueryPerformanceCounter  amp timerTemp        if  prevInit                prevInit   1          prevTime   timerTemp QuadPart            else if   currInit                currInit   1          currTime   timerTemp QuadPart            else               prevTime   currTime          currTime   timerTemp QuadPart             lua pushnumber L  timerTemp QuadPart       return 1     static int getNanoElapsed lua State  L        double mNanoSecondsPerCount   1000000000  double FrequencyCountPerSec      double elapsedNano    currTime - prevTime  mNanoSecondsPerCount      lua pushnumber L  elapsedNano       return 1      int luaopen HighResolutionTimer  lua State  L         static const luaL reg mylib                       readHiResTimerFrequency   readHiResTimerFrequency             storeTime   storeTime             getNanoElapsed   getNanoElapsed            NULL  NULL      sentinel                luaL register L  timer  mylib        return 1      --  --  Now lets get it loaded up in a lua script  HighResTimer lua    Note  I compiled the HighResTimer c to a shared library  Timer so     bin lua ------------------------------------ ---HighResTimer lua by Cody Duncan ---Wraps the High Resolution Timer Functions in ---   Timer so ------------------------------------  package cpath      Timer so      --assuming Timer so is in the same directory require  HighResolutionTimer     --load up the module timer readHiResTimerFrequency    --stores the tickFrequency   --call this before code that is being measured for execution time function start       timer storeTime    end  --call this after code that is being measured for execution time function stop       timer storeTime    end  --once the prior two functions have been called  call this to get the  --time elapsed between them in nanoseconds function getNanosElapsed       return timer getNanoElapsed    end   --  --  and Finally  utilize the timer  TimerTest lua       bin lua ------------------------------------ ---TimerTest lua by Cody Duncan --- ---HighResTimer lua and Timer so must  ---   be in the same directory as  ---   this script  ------------------------------------  require    HighResTimer    start    for i   0  3000000 do io write     end --do essentially nothing 3million times  stop     --divide nanoseconds by 1 million to get milliseconds executionTime   getNanosElapsed   1000000   io write  execution time     executionTime   ms n      Note  Any comments were written after pasting the source code into the post editor  so technically this is untested  but hopefully the comments didn t befuddle anything  I will be sure to come back and provide a fix if it does

User · Answer

Kevlar is correct    An alternative to a custom DLL is Lua Alien

User · Answer

Kevlar is correct    An alternative to a custom DLL is Lua Alien

User · Answer

I use LuaSocket to get more precision   require  socket  print  Milliseconds       socket gettime   1000    This adds a dependency of course  but works fine for personal use  in benchmarking scripts for example

User · Answer

Get current time in milliseconds   os time    os time   return sec    only   posix clock gettime clk   https   luaposix github io luaposix modules posix time html clock gettime  require posix  clock gettime 0  return sec  nsec   linux time h    man clock gettime        The IDs of the various system clocks  for POSIX 1b interval timers        define CLOCK REALTIME                  0  define CLOCK MONOTONIC                 1  define CLOCK PROCESS CPUTIME ID        2  define CLOCK THREAD CPUTIME ID         3  define CLOCK MONOTONIC RAW             4  define CLOCK REALTIME COARSE           5  define CLOCK MONOTONIC COARSE          6   socket gettime    http   w3 impa br  diego software luasocket socket html gettime  require socket  gettime   return sec xxx   as waqas says    compare  amp  test  get millisecond lua  local posix require posix  local socket require socket   for i 1 3 do     print  os time         print  posix clock gettime 0        print  socket gettime         print       posix nanosleep 0  1  -- sec  nsec end   output  lua get millisecond lua 1490186718 1490186718      268570540 1490186718 2686  1490186718 1490186718      268662191 1490186718 2687  1490186718 1490186718      268782765 1490186718 2688

User · Answer

I made a suitable solution for lua on Windows  I basically did what Kevlar suggested  but with a shared library rather than a DLL  This has been tested using cygwin   I wrote some lua compatible C code  compiled it to a shared library   so file via gcc in cygwin   and then loaded it up in lua using package cpath and require     Wrote an adapter script for convenience  Here is all of the source   first the C code  HighResTimer c                                                                     HighResTimer c by Cody Duncan      compile with   gcc -o Timer so -shared HighResTimer c -llua5 1   compiled in cygwin after installing lua  cant remember if I       installed via setup or if I downloaded and compiled lua        probably the former                                                                    include  lt windows h gt   typedef unsigned   int64 u64  double mNanoSecondsPerCount    include  lua h   include  lualib h   include  lauxlib h    int prevInit   0  int currInit   0  u64 prevTime   0  u64 currTime   0  u64 FrequencyCountPerSec   LARGE INTEGER frequencyTemp  static int readHiResTimerFrequency lua State  L        QueryPerformanceFrequency  amp frequencyTemp       FrequencyCountPerSec   frequencyTemp QuadPart      lua pushnumber L  frequencyTemp QuadPart       return 1     LARGE INTEGER timerTemp  static int storeTime lua State  L        QueryPerformanceCounter  amp timerTemp        if  prevInit                prevInit   1          prevTime   timerTemp QuadPart            else if   currInit                currInit   1          currTime   timerTemp QuadPart            else               prevTime   currTime          currTime   timerTemp QuadPart             lua pushnumber L  timerTemp QuadPart       return 1     static int getNanoElapsed lua State  L        double mNanoSecondsPerCount   1000000000  double FrequencyCountPerSec      double elapsedNano    currTime - prevTime  mNanoSecondsPerCount      lua pushnumber L  elapsedNano       return 1      int luaopen HighResolutionTimer  lua State  L         static const luaL reg mylib                       readHiResTimerFrequency   readHiResTimerFrequency             storeTime   storeTime             getNanoElapsed   getNanoElapsed            NULL  NULL      sentinel                luaL register L  timer  mylib        return 1      --  --  Now lets get it loaded up in a lua script  HighResTimer lua    Note  I compiled the HighResTimer c to a shared library  Timer so     bin lua ------------------------------------ ---HighResTimer lua by Cody Duncan ---Wraps the High Resolution Timer Functions in ---   Timer so ------------------------------------  package cpath      Timer so      --assuming Timer so is in the same directory require  HighResolutionTimer     --load up the module timer readHiResTimerFrequency    --stores the tickFrequency   --call this before code that is being measured for execution time function start       timer storeTime    end  --call this after code that is being measured for execution time function stop       timer storeTime    end  --once the prior two functions have been called  call this to get the  --time elapsed between them in nanoseconds function getNanosElapsed       return timer getNanoElapsed    end   --  --  and Finally  utilize the timer  TimerTest lua       bin lua ------------------------------------ ---TimerTest lua by Cody Duncan --- ---HighResTimer lua and Timer so must  ---   be in the same directory as  ---   this script  ------------------------------------  require    HighResTimer    start    for i   0  3000000 do io write     end --do essentially nothing 3million times  stop     --divide nanoseconds by 1 million to get milliseconds executionTime   getNanosElapsed   1000000   io write  execution time     executionTime   ms n      Note  Any comments were written after pasting the source code into the post editor  so technically this is untested  but hopefully the comments didn t befuddle anything  I will be sure to come back and provide a fix if it does

User · Answer

In standard C lua  no   You will have to settle for seconds  unless you are willing to modify the lua interpreter yourself to have os time use the resolution you want   That may be unacceptable  however  if you are writing code for other people to run on their own and not something like a web application where you have full control of the environment   Edit  another option is to write your own small DLL in C that extends lua with a new function that would give you the values you want  and require that dll be distributed with your code to whomever is going to be using it

User · Answer

If you re using lua with nginx openresty you could use ngx now   which returns a float with millisecond precision

[time] Lua - Current time in milliseconds

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