Mantis: 0000474 AccurateDateAndTime harvested?

Keith Hodges keith_hodges at yahoo.co.uk
Fri Oct 13 04:09:14 UTC 2006


Giovanni Corriga wrote:
> Il giorno gio, 12/10/2006 alle 21.06 +0200, stephane ducasse ha scritto:
>   
>> Hi
>>
>> I will release RC2.
>> But we should not add more to it because this will never stop.
>>     
>
> yes, Yes, YES. Unless it's a serious showstopper, it should be punted to
> either 3.9.1 or 3.10.
>
> 	Giovanni
>
>   
I agree,  but I think some improvements can be made...

cc from note in mantis.

I made a variant which effectively uses the millisecond clock for the 
time, and the second clock for the date. I do this in anticipation of 
the day when the vm primitives give us useful milliseconds (or 
nanoseconds) since midnight.  [ Is this likely to happen? ]

I also discovered that avoiding the use of Duration in the instantiation 
of DateAndTime improves performance by a factor of x3 on Andreas' 
observation. Making an accessor to set the instance vars directly 
without normalizing (I don't understand the purpose of normalising) 
boosts that to a factor of x4.

Then removing the semaphore and use of the class var LastTicks improves 
speed up to a pretty wizzy 90x the original.

Perhaps for those of us who dont care about this
  (DateAndTime now) <= (DateAndTime now) is always true*

would prefer the quicker version which I have christened.

DateAndTime-i-#rightNow

:-)

Keith
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