Nginx mutli-threaded plugin

[Fasih]

Thank you Maxim. Will try to see if I can get to the single threaded model.
Basically when I was talking about accept_mutex, what I meant was, if the
worker thread is busy with my cpu-intensive work, I would obviously want
the other workers to take over. IIUC, if I have the accept mutex I am the
one who will take the requests, is it possible that my worker plugin is
caught up doing the work *and* has not released the mutex? In other words,
is it possible that my CPU intensive operation prevents other workers who
are free from taking requests with any configuration option
enabled/disabled.


On Wed, Jan 2, 2013 at 2:49 AM, Maxim Dounin <mdounin at mdounin.ru> wrote:

> Hello!
>
> On Tue, Jan 01, 2013 at 11:57:30PM +0530, Fasih wrote:
>
> > Hi guys
> >
> > I need to write a plugin which does some CPU intensive work. I want to be
> > able to create a thread which does some work and once done post an event
> > into nginx thread via ngx_add_timer. I tried compiling my plugin with
> > NGX_THREADS=pthread but that doesnt configure saying that the threading
> > support is broken.  I can obviously switch to a single threaded mode but
> > that would be significantly difficult for me and would prefer to use only
> > as the very last resort.
> >
> > Can you please advice how to go about doing this? I am considering
> pulling
> > out the usage of 'ngx_event_timer_mutex' outside #if NGX_THREADS.
> Frankly I
> > am surprised how no other plugin had this kind of requirement, the
> "broken
> > support" commit has been there since quite some time now.
>
> Threading support as currently present was an experiment, and it's
> broken for a long time (some very limited part of it is still used
> on win32, but it's different story).  I wouldn't expect you'll be
> able to work with threads without problems.
>
> > One final question, if I do the CPU intensive work in the nginx thread
> and
> > I have <cpu-cores> number of workers, how would the system behave? Will
> > accept_mutex on/off change the behavior?
>
> Accept mutex only ensures no two processes try to accept new
> connections at the same time, and it doesn't care how do you
> handle requests.  Obviously enough it will change the behaviour,
> much like in any other case.
>
> --
> Maxim Dounin
> http://nginx.com/support.html
>
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>
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