From: David MacMahon <davidm@...>
Date: 2013-08-22T16:01:16-07:00
Subject: [ruby-core:56787] Re: [ruby-trunk - Feature #8809][Open]	Process.clock_getres


On Aug 22, 2013, at 3:37 PM, Tanaka Akira wrote:

> 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.

Agreed.  Plus, if someone really wants, they can request nanosecond precision, which is all that clock_getres supports (at least on Linux).

> 
>>> 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.

I know it's not SI, but I often use ASCII "u" for Greek m ("�"), so :microsecond would be aliased by :us.

> Someone may argue :hz should be :Hz.

No doubt! :-)

> I feel :float_s is bit curious.

How about separating the type and the resolution into two different parameters?

    Process.clock_getres(Process::CLOCK_MONOTONIC, :float, :second)

...or...

    Process.clock_getres(Process::CLOCK_MONOTONIC, Float, :second)

> 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.

Agreed.  I think the main feature is great!

> 
>>> 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.

Sounds good.

Dave