Re: [boost] Future of Boost.Thread, date-time, and C++0x

From: David Abrahams (dave_at_[hidden])
Date: 2007-10-16 15:44:34

on Mon Oct 08 2007, "Phil Endecott" <spam_from_boost_dev-AT-chezphil.org> wrote:

> Jeff Garland wrote:
>> At the Kona meeting (just finished) the standard committee made very 
>> significant progress on threading for C++0x -- voting in a proposal written by 
>> Howard H, Beman, Anthony Williams, myself, and others -- subject to wording 
>> changes to be made by a small drafting committee.  Basically we were in 
>> agreement on semantics, but even after several late night drafting sessions 
>> people weren't happy with the standardeze.
>>
>> While much of the proposal is based on Boost.thread it has some serious 
>> departures in the way mutexes and guard interfaces work, it's use of date-time 
>> types for clock/timing interfaces and such.
>
> This reminds me: I thought I posted something about this when Howard 
> sent his proposal to this list, but it seems to have been lost in an 
> email black-hole.  Howard's code included timed operations that are 
> templated on the time type, which (presumably) allows an implementation 
> to provide versions for each of that platform's standard time types.  
> This reminded me of some presentations about power saving at 
> LinuxConf.EU: apparently reducing the number of timer interrupts is 
> greatly beneficial to increasing energy efficiency, and one way to 
> achieve this is to align all applications' periodic wakeups.  Very 
> often, we want to timeout after "about a second" but will actually 
> specify a timeout value of "exactly 1.0000000 seconds"; if the API 
> allowed us to indicate, for example, "between 0.1 and 1.5 seconds", or 
> "1 second +/- 10%", then some hidden power-saving wakeup-alignment 
> algorithm could be applied.  

Agreed, this is hugely important.  However, I think the standardese
may be easier than that: unless we think some programs need both exact
and flexible timeouts, we can leave it up to the implementation to
interpret the timeout value.

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com