Re: [boost] [GSoC] Scheduled Executors beta 1 release

Subject: Re: [boost] [GSoC] Scheduled Executors beta 1 release
From: Agustín K-ballo Bergé (kaballo86_at_[hidden])
Date: 2014-07-25 10:39:42

On 24/07/2014 10:57 p.m., Ian Forbes wrote:
> Hello,
>
> I am working on implementing scheduled executors as part of GSoC 2014 and am ready to announce my beta 1 release
>
> Basically a scheduled executor is an executor which guarantees that a certain task won't be run before a certain time point.
>
> I'm mostly interested in people reading this part of the README: https://github.com/BoostGSoC14/boost.thread.executors#possible-changes--rfcs
> This details possible changes that could be made and I would like some feedback on them as these items have both pros and cons.

 > `sync_timed_queue` and `scheduled_executor` have template parameters 
for a `Clock`.

There is hardly a need for this.

 > This defaults to `boost::chrono::steady_clock`. There is a static 
assert to ensure that `Clock` is steady.

Given that you restrict everything to steady clocks, What's the 
rationale for restricting to a single `time_point` instantiation only? 
Furthermore, restricting to a single `duration` makes absolutely no 
sense. Any `duration` can be mapped to a steady `time_point` and still 
meet the timing specifications.

 > This is also satisfied by `high_resolution_clock` (...)

It is not.

 > (...) is no longer a factor like with `steady_clock` and 
`high_resolution_clock` which are wall clocks.

They are not (or may not be). The only guarantees are that 
`system_clock` represents a wall clock, `steady_clock` represents a 
clock that may not be adjusted, `high_resolution_clock` represents a 
clock with the shortest tick period. In particular, `steady_clock` and 
`high_resolution_clock` may be aliases for other clocks.

I've glanced at the code, and noticed that `time_point`s and `duration`s 
are taken by value. The standard takes them by `const&` so I think you 
should follow that.

Regards,
-- 
Agustín K-ballo Bergé.-
http://talesofcpp.fusionfenix.com