[Django] #35332: Bad performance in django.template.load.render_to_string

[Django]

#35332: Bad performance in django.template.load.render_to_string
-------------------------------------+-------------------------------------
Reporter: Zeyad | Owner: nobody
Moustafa |
Type: | Status: new
Uncategorized |
Component: Template | Version: 5.0
system | Keywords: performance
Severity: Normal | templates jinja
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
Hi folks, thanks for your great job here.

So with the rise of rust we are seeing, I told myself to make a component
of Django components in rust so we can get a better performance as memory
safety and all of these features from rust.

While searching I discovered a great package called mini-jinja. so I just
wanted to compare its performance with the Django template engine
performance to figure out if what I am doing is good for the community or
not. so here is the code I have written to know about the performance.


{{{
# mini-jinja.py
from minijinja import Environment


with open('test.html', 'r') as file:
template = file.read()


env = Environment(
templates={
'test': template
}
)

result = env.render_template('test', nums=range(1000000))

}}}

and this is the result of the testing.

{{{
❯ time python mini-jinja.py
python mini-jinja.py 1.27s user 0.03s system 99% cpu 1.302 total

dummy/python-tests/copper via 🐍 v3.10.12 (.venv)
❯ time python mini-jinja.py
python mini-jinja.py 1.23s user 0.03s system 99% cpu 1.259 total
}}}


and this is how I tested it in django
first created main.py file with this contents


{{{
import time
from django.template.loader import render_to_string


def render():
start = time.time()
_template = render_to_string("test.html", {"nums": range(1000000)})
end = time.time()
print(end - start)
}}}

and then I opened the django shell and imported the main file and then
typed render and here is what I got


{{{
❯ python manage.py shell
Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> import main
>>> main.render()
28.39499545097351
>>>
}}}
and here is the test.html I was using for both the tests

{{{
{% for num in nums%}

<h1>{{num}}</h1>

{% endfor %}
}}}

So here is my question. why a big difference between both of them?? is
there anything I have done wrong or this is related to the nature of
python?? I just opened this issue to know if it will be really good for
the Django community to create a template engine using rust built on top
of Mini-jinja or if there is something I have to modify in my tests to get
the real result??
--
Ticket URL: <https://code.djangoproject.com/ticket/35332>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.

[Django]

#35332: Bad performance in django.template.load.render_to_string
-------------------------------------+-------------------------------------

Reporter: Zeyad Moustafa | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Template system | Version: 5.0
Severity: Normal | Resolution: needsinfo
Keywords: performance | Triage Stage:
templates jinja | Unreviewed
Has patch: 0 | Needs documentation: 0

Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------

Changes (by Mariusz Felisiak):

* resolution: => needsinfo
* status: new => closed
* type: Uncategorized => Cleanup/optimization

Comment:

Hi, I don't think you've explained the issue in enough detail to confirm a
bug in Django. Please reopen the ticket if you can debug your issue and
provide details about why and where Django is at fault and what we could
do better. Performance improvements are welcome, but you have to propose
concrete things. You can start a discussion on the DevelopersMailingList,
where you'll reach a wider audience and see what other think.
--
Ticket URL: <https://code.djangoproject.com/ticket/35332#comment:1>

[Django]

#35332: Bad performance in django.template.load.render_to_string
-------------------------------------+-------------------------------------
Reporter: Zeyad Moustafa | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Template system | Version: 5.0
Severity: Normal | Resolution: needsinfo
Keywords: performance | Triage Stage:
templates jinja | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------

Comment (by Adam Johnson):

Yeah, there’s no bug here. 30 times slowness is about right for a
Rust/Python comparison. Also the benchmark is minimal and unrealistic, the
margin should be less (maybe not much) for a typical template that has far
fewer nodes.

This would be an interesting forum discussion - not a bug in the bug
tracker. I’d be interested in seeing more. And if you want to get into
optimizing specific parts of the template engine, I’d be up for reviewing
some PRs. My recent work on the system checks may be a nice guide:
https://adamj.eu/tech/2024/03/23/django-optimizing-system-checks/
--
Ticket URL: <https://code.djangoproject.com/ticket/35332#comment:2>

[Django]

#35332: Bad performance in django.template.load.render_to_string
-------------------------------------+-------------------------------------
Reporter: Zeyad Moustafa | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Template system | Version: 5.0
Severity: Normal | Resolution: needsinfo
Keywords: performance | Triage Stage:
templates jinja | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------

Comment (by Zeyad Moustafa):

OK. I opened a discussion here https://forum.djangoproject.com/t/getting-a
-low-performance-in-django-template-loader-render-to-string/29488 and the
person I was talking with told me the same thing that the benchmarking is
not that good.

and I decided to make this template engine in rust. but I don't plan to
integrate it into Django directly. I will start by building a standalone
package and when I get a good community of people who are using it and
testing it I might open a PR and integrate it to Django. but thanks for
letting me know that you are interested in this idea.
--
Ticket URL: <https://code.djangoproject.com/ticket/35332#comment:3>