From: Tanaka Akira <akr@...>
Date: 2013-08-23T07:37:48+09:00
Subject: [ruby-core:56786] Re: [ruby-trunk - Feature #8809][Open]	Process.clock_getres

2013/8/23 David MacMahon <davidm@astro.berkeley.edu>:
>>
>>  Process.clock_getres(Process::CLOCK_MONOTONIC) #=> 1.0e-09
>>  Process.clock_getres(Process::CLOCK_MONOTONIC_COARSE) #=> 0.00400025
>>
>> The result means that the resolution of CLOCK_MONOTONIC is 1ns and
>> the resolution of CLOCK_MONOTONIC_COARSE is 4.00025ms.
>
> Did you consider having these methods return Rational rather than Float?

Process.clock_getres can return rational if it supports
:rational_second as a unit.

The current default of unit is :float_second and
I think float is good enough.

>>  Process.clock_getres(:SUS_GETRUSAGE_BASED_CLOCK_PROCESS_CPUTIME_ID, :hertz) #=> 1000000.0
>
> How would you feel about supporting :ns and :hz as equivalents for :nanosecond and :hertz?

It is difficult to support :microsecond in that style
because the SI prefix, Greek m, is not representable in ASCII.

Someone may argue :hz should be :Hz.

I feel :float_s is bit curious.

So it is difficult to adopt :ns style as canonical style of unit.

I think several aliases are possible but
I'd like to concentrate to main feature.
The discussion for what aliases should be added or not can be diverge.

>> Note that
>> Process.clock_getres(:POSIX_TIMES_BASED_CLOCK_PROCESS_CPUTIME_ID, :hertz) is the clock ticks per second (CLK_TCK) and
>> Process.clock_getres(:ISO_C_CLOCK_BASED_CLOCK_PROCESS_CPUTIME_ID, :hertz) is CLOCK_PER_SEC.
>> I wanted to access them easily to investigate emulated clock behaviors on
>> various OSes.
>
> Those are some long symbols!  Are these intended only for experimental/investigative use?

I choose the long symbols that is longer than Process::CLOCK_PROCESS_CPUTIME_ID.
Basically users should use Process::CLOCK_PROCESS_CPUTIME_ID if no reason.
-- 
Tanaka Akira