Модуль clock¶

The clock module returns time values derived from the Posix / C CLOCK_GETTIME function or equivalent. Most functions in the module return a number of seconds; functions whose names end in «64» return a 64-bit number of nanoseconds.

clock.time()¶

clock.time64()¶

clock.realtime()¶

clock.realtime64()¶

The wall clock time. Derived from C function clock_gettime(CLOCK_REALTIME). This is the best function for knowing what the official time is, as determined by the system administrator.

Return:	seconds or nanoseconds since epoch (1970-01-01 00:00:00), adjusted.
Rtype:	number or number64

Example:

-- This will print an approximate number of years since 1970.
clock = require('clock')
print(clock.time() / (365*24*60*60))

See also fiber.time64 and the standard Lua function os.clock.

clock.monotonic()¶

clock.monotonic64()¶

The monotonic time. Derived from C function clock_gettime(CLOCK_MONOTONIC). Monotonic time is similar to wall clock time but is not affected by changes to or from daylight saving time, or by changes done by a user. This is the best function to use with benchmarks that need to calculate elapsed time.

Return:	seconds or nanoseconds since the last time that the computer was booted.
Rtype:	number or number64

Example:

-- This will print nanoseconds since the start.
clock = require('clock')
print(clock.monotonic64())

clock.proc()¶

clock.proc64()¶

The processor time. Derived from C function clock_gettime(CLOCK_PROCESS_CPUTIME_ID). This is the best function to use with benchmarks that need to calculate how much time has been spent within a CPU.

Return:	seconds or nanoseconds since processor start.
Rtype:	number or number64

Example:

-- This will print nanoseconds in the CPU since the start.
clock = require('clock')
print(clock.proc64())

clock.thread()¶

clock.thread64()¶

The thread time. Derived from C function clock_gettime(CLOCK_THREAD_CPUTIME_ID). This is the best function to use with benchmarks that need to calculate how much time has been spent within a thread within a CPU.

Return:	seconds or nanoseconds since thread start.
Rtype:	number or number64

Example:

-- This will print seconds in the thread since the start.
clock = require('clock')
print(clock.thread64())

clock.bench(function[, ...])¶

The time that a function takes within a processor. This function uses clock.proc(), therefore it calculates elapsed CPU time. Therefore it is not useful for showing actual elapsed time.

Параметры:	function (function) – function or function reference ... – whatever values are required by the function.
Return:	table. first element - seconds of CPU time, second element - whatever the function returns.

Example:

-- Benchmark a function which sleeps 10 seconds.
-- NB: bench() will not calculate sleep time.
-- So the returned value will be {a number less than 10, 88}.
clock = require('clock')
fiber = require('fiber')
function f(param)
  fiber.sleep(param)
  return 88
end
clock.bench(f, 10)

Версия:

Модуль clock¶