[Django]-Django development server reload takes too long

(for guys still googling the answer)

I had similar problem using Vagrant (on Windows host machine). Solution for me was move virtualenv folder away from synced /vagrant. Default settings of synced folders uses VirtualBox provider and that’s the problem. We can read about this in another sync methods from Vagrant official documentation:

In some cases the default shared folder implementations (such as VirtualBox shared folders) have high performance penalties. If you’re seeing less than ideal performance with synced folders, NFS can offer a solution.

and

SMB is built-in to Windows machines and provides a higher performance alternative to some other mechanisms such as VirtualBox shared folders.

See Vagrant shared folders benchmark for extra info.

The manpage for waitpid says:
The waitpid() system call suspends execution of the calling process until a child specified by pid argument has changed state. By default, waitpid() waits only for terminated children, but this behavior is modifiable via the options argument, as described below.
http://linux.die.net/man/2/waitpid

Why is it taking so long for the child process to change state? The django manage.py runserver command is a very thin wrapper over ANOTHER runserver command:

 2533 pts/0    Ss     0:00  \_ bash
28374 pts/0    S+     0:00  |   \_ ../env/bin/python ./manage.py runserver
 7968 pts/0    Sl+   20:26  |       \_/home/sandford/workspace/usgm_apps/usgm_apps/../env/bin/python ./manage.py runserver

So the “boss” (28374) notices a change on a file and tells the “worker” (7968) to exit. Once the “worker” exits, it starts up a new worker with the new source files. The “worker” is taking a long time to exit.

Or OSX THINKS it’s taking a long time to exit. If the OS gets behind on bookkeeping in the kernel for some reason and delays updating state you could end up with a delay like this.

Or perhaps there’s something else entirely going on. It’s perplexing.

In my case, it was caused by the DjangoWhiteNoise module being loaded in the wsgi.py file. After I added a condition that disabled the module in my development environment, the server reload time decreased substantially.