Possible performance regression related to django signals instrumentation

[ron8mcr]

How do you use Sentry?

Self-hosted/on-premise

Version

1.12.1

Steps to Reproduce

Updated sentry-sdk from 1.9.8 to 1.12.1.

Expected Result

Overall project performance not changed

Actual Result

Performance decreased for about 25%.

Looks like instrumentation of some django signals (#1526) brought some overhead.
In my specific example, I've used https://github.com/matthewwithanm/django-imagekit for thumbnails generation. And this lib uses post_init signal to track changes of ImageField values.
For cases when there is about 1000 instances in response of DRF API method, post_init handler is called for a lot of times (even for models that actually does not have any ImageField). imagekit itself implements a fast check if handler should be called. However, looks like instrumentation of this slow down overall time of response.

See screenshots with example request. The first one is with commented out patch_signals call:

The second is with enabled signals instrumentation:

I think that sentry option that allow to disable instrumentation of some specific signals/receivers will allow to solve this problem. Or maybe option that will allow to disable specific instrumentation.

P.S. I used following monkey-patch to disable signals instrumentation and restore previous performance:

from sentry_sdk.integrations import django
django.patch_signals = lambda: None

sentry_sdk.init(
	"integrations": [django.DjangoIntegration()],
	"dsn": "dsn",
)

[kanu]

I would also love to have this configurable. On signal or sender level.
What I additionally noticed was that I am not able to easily see the connected receivers of a signal by calling
e.g. post_save._live_receivers(AnyModel) as they are wrapped now. But this should be solvable by using functools.wraps to update the wrapper function : signature was fixed in #1700

[antonpirker]

Hey @kanu nice to see you here!

We have an issue for adding a configuration to disable signal instrumentation: #1739

[ron8mcr]

@antonpirker I've checked performance with changes from #1929 (sentry-sdk==1.17.0) and it solved the problem. Thanks for fixing this!