Re: DateTime::Lite

On Tue, 25 Nov 2008, Daisuke Maki wrote:

> Yes, I wrote a crude benchmark script in 
> DateTime-Lite/tools/benchmar/load_times.pl
> If you don't load arithmetic and strftime, DT::Lite is twice as fast plain 
> DT.
>
>               Rate           dt dt_lite_full      dt_lite
> dt           46.6/s           --         -13%         -49%
> dt_lite_full 53.7/s          15%           --         -41%
> dt_lite      91.7/s          97%          71%           --
>
>
> And again, /I know/ this isn't that much of a practical problem, because the 
> engineer's correct answer is "if the load time is slow, load it once, and use 
> some sort of persistent environment". This is mainly a marketing issue to my 
> audience, who, for example, includes CGI developers (i.e., persistent 
> environment isn't an option).
>
> BTW, dt_lite_full is almost equivalent to using DateTime.pm, but I /think/ 
> the difference comes from the tweak I did to switch method calls to function 
> calls. That can probably be tweaked in DateTime.pm, if you want me to apply 
> it.

Isn't this just a test of load times? How could using methods vs functions 
make any difference to a module's load times?

I suspect the difference may come from several things:

1. Not loading several modules, including XSLoader and Params::Validate.

2. Not loading an XS component.

3. Not loading a default locale - DateTime ends up loading the en_US 
locale when DateTime.pm is loaded. Your benchmark might actually be 
_understating_ that, since your benchmark doesn't force this module to be 
reloaded as well.

> Creating GVs for each timezone is a waste. Creating one class, then creating 
> instances for each timezones are much cheaper. I discussed this briefly when 
> I was trying to do DateTime::TimeZone::XS, but I got warnocked.

Right, I do remember that.

Yes, it makes sense that not creating all those namespaces would reduce 
memory usage.

I'm a little leary of changing things now, since it'd be backwards 
incompatible. I wonder if anyone actually relies on those objects having a 
namespace that includes the time zone though.


-dave

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