Re: [Openinteract-dev] Using FastCGI as development plaftorm

[<ant...@he...>]

Perrin Harkins wrote:
>>it _still_ did all of the initializations twice 
>>with OI2.
> I haven't looked at how OI2's startup is organized, but this is probably
> fixable.  Things called from PerlModule or PerlRequire will be run
> twice, but modules loaded inside of that will not.

OI2 initializes a singleton Context object on startup (through 
PerlRequiring a startup.pl) which contains quite a lot of various data. 
I'm not quite sure how to prevent the Context from initializing twice 
but I suppose it could be fixed.

Hmm.. Could we just check if the singleton object already exists in the 
memory and not initialize it twice? Why didn't I think of this before? 
But well I'm not bugged by this anymore so those who are can try if it 
works ;)

> I still don't understand what you're saying FastCGI does though.
> Doesn't it also keep the interpreter alive in memory?

It doesn't do anything special. If I restart apache, the FastCGI server 
stops and it starts again only when I issue the next request for it. 
This way it gets fully initialized with the current data.

Since we can't use Apache::Reload (at least atm) this is what you would 
want it to do when developing for OI2.

At least for me it is a huge difference that I don't have to watch the 
mod_perl apache to start (which takes quite some time) and issue my 
request after it has finished - I can just issue the request and it is 
executed instantly when the initialization is completed.

> No, it's just a fork.  Forking is very fast on linux and none of the
> memory gets copied until the pages are dirty.

Yes, it is just a fork and the forking is really cheap but there is no 
way to prevent mod_perl from polluting also much of the static data 
shared with the parent process according to this:

http://perl.apache.org/docs/1.0/guide/performance.html#toc_Sharing_Memory

Since the execution path of OI2 is long, large amounts of the data gets 
dirty along the way.

> FastCGI forks too.

By default, no it doesn't. It's just a single Perl interpreter serving 
requests one by one.

- Antti