[Django] #25228: Performance degradation of template rendering
Django
---------------------------------+--------------------
Reporter: yml | Owner: nobody
Type: Bug | Status: new
Component: Template system | Version: 1.8
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
---------------------------------+--------------------
I noticed a performance regression after an upgrade from django `1.6.11`
to `1.8.3` ; the project does an extensive usage of `include` and
`extends`. I have simplified the problem into a mini django project on
github called: [https://github.com/yml/django-perfo-regression django-
perfo-regression]. This project contains 2 branches (different settings)
and 4 tests used to time various cases of template rendering:
* Standalone
* `include`
* `extends`
* `include` & `extends`
Depending on the settings there has been 2 major changes in the
performance characteristic over the releases since django 1.4.
* `1.7` doubled the rendering time with DEBUG=True for `include`
* `1.8.3` degraded the simplified production ready (`DEBUG=False` &
`cached.Loader`)
This [https://docs.google.com/spreadsheets/d/1v-cXcx8lLOF7sphtvdofU-
30GmpPCyvgn1TjIRJk4OM/edit?usp=sharing spreadsheet] contains the result I
am observing on my laptop.
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Ticket URL: <https://code.djangoproject.com/ticket/25228>
Django <https://code.djangoproject.com/>
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Django
Reporter: yml | Owner: nobody
Type: Bug | Status: new
Component: Template system | Version: 1.8
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timgraham):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
Comment:
Preston mentioned in IRC that a391b17ad24bc5f255a3928c23c158c79004c656
should improve performance on 1.9 -- did you check that? Identifying the
commits where performance decreased would be helpful.
--
Ticket URL: <https://code.djangoproject.com/ticket/25228#comment:1>
Django
Reporter: yml | Owner: nobody
Type: Bug | Status: new
Component: Template system | Version: 1.8
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by yml):
I did another run with all the releases from 1.8 series and django-tip. I
confirm that django-tip improves the situation but it is still slower
than the releases before `1.8.3` :
|| ||= standalone =||= extends
=||= include =|| include & extends =||
|| 1.8.0 ||0.520450115204 ||0.841553926468 ||
4.12727284431 ||7.55168485641 ||
|| 1.8.1 ||0.549235105515 ||0.868353843689
||4.21892404556 ||7.14691209793 ||
|| 1.8.2 || 0.591598987579 ||0.840734004974
||4.22193288803 ||6.90138411522 ||
|| 1.8.3 || 1.48196005821 ||1.79811000824 ||
5.08307695389 || 8.11770391464 ||
|| tip 2015-08-10 || 0.620449066162 ||0.92530298233
||4.18256998062 || 7.9185230732 ||
This was done using the following command in this [https://github.com/yml
/django-perfo-regression repo]:
`tox -e
py27-django-1.8.0,py27-django-1.8.1,py27-django-1.8.2,py27-django-1.8.3,py27
-django-tip`
--
Ticket URL: <https://code.djangoproject.com/ticket/25228#comment:2>
Django
Reporter: yml | Owner: nobody
Type: Bug | Status: new
Component: Template system | Version: 1.8
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by timgraham):
If you could bisect to find the commit where the performance change
significantly, that will help assess what (if anything) can be done.
--
Ticket URL: <https://code.djangoproject.com/ticket/25228#comment:3>
Django
Reporter: yml | Owner: nobody
Type: Bug | Status: new
Component: Template system | Version: 1.8
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by yml):
`git bisect` between 1.8.2 and 1.8.3 point its finger on this commit:
```
b16f84f15b1344d2a3df8149565cfc8de803eb77 is the first bad commit
commit b16f84f15b1344d2a3df8149565cfc8de803eb77
Author: Tim Graham <timog...@gmail.com>
Date: Wed May 27 09:19:19 2015 -0400
[1.8.x] Refs #24836 -- Reverted "Simplified the lazy CSRF token
implementation in csrf context processor."
This reverts commit 8099d33b6553c9ee7de779ae9d191a1bf22adbda as it
caused
a regression that cannot be solved without changing force_text() which
has
a small risk of introducing regressions. This change will remain in
master
along with an update to force_text().
:040000 040000 79f27245b250a4ac0c65a4ccef0b8db107432312
6c6a96934b66615d663375cc13199cf50c6fd1ec M django
:040000 040000 c977299c605629e42fd2ec7bb53264d5ac25db78
9eef450849404da0e8f20c292b8aa8b544176681 M docs
:040000 040000 96fa0ceb7be7bd9ca14eded3ca98478a22ce8f39
e3c95cc6052e620319c7ef2d64a1716825839414 M tests
````
Here it is a link to the commit that introduce the performance regression
[https://github.com/django/django/commit/b16f84f15b1344d2a3df8149565cfc8de803eb77
diff on github]
--
Ticket URL: <https://code.djangoproject.com/ticket/25228#comment:4>
Django
Reporter: yml | Owner: nobody
Type: Bug | Status: new
Component: Template system | Version: 1.8
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by timgraham):
That optimization (added in 1.8) has been kept on master with an alternate
fix (70be31bba7f8658f17235e33862319780c3dfad1) but was deemed too risky to
backport to 1.8.
I am not sure what can be done to resolve this ticket absent a proposed
patch. It's possible the correct fix cannot be as fast as the buggy fix.
Do you have any interest in looking at it yourself? If not, I guess we can
accept the ticket and see if anyone comes along to take a closer look.
--
Ticket URL: <https://code.djangoproject.com/ticket/25228#comment:5>
Django
Reporter: yml | Owner: nobody
Type: Bug | Status: closed
Component: Template system | Version: 1.8
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timgraham):
* status: new => closed
* resolution: => needsinfo
--
Ticket URL: <https://code.djangoproject.com/ticket/25228#comment:6>