# PEP 669: Low Impact Monitoring for CPython

**URL:** <https://discuss.python.org/t/pep-669-low-impact-monitoring-for-cpython/13018>\
**Category:** PEPs\
**Created:** [January 10, 2022, 3:31pm UTC](https://discuss.python.org/t/pep-669-low-impact-monitoring-for-cpython/13018 "2022-01-10T15:31:08Z")\
**Posts on this page:** 1\
**Showing post:** 47

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**Author:** ![nedbat](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/nedbat/32/8744_2.png) [@nedbat](https://discuss.python.org/u/nedbat)\
**Post date:** [November 9, 2022, 11:58pm UTC](https://discuss.python.org/t/pep-669-low-impact-monitoring-for-cpython/13018/47 "2022-11-09T23:58:52Z")

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I’m still concerned that this point hasn’t been addressed:

> [@nedbat](#):
>
> > All branches from that point. I can see the advantage of tracking each direction independently, but it would be a special case and would impact performance and memory consumption.
> 
> You’ve placed great emphasis on the idea of disabling a callback after it has fired. In order to measure branch coverage, I need to know all of the branches that have been taken. If I disable the branch event once I’ve received it, and that disables all branches from that point, then I don’t have the information I need. That’s why I said it would be useless to disable the branch event if it didn’t take the destination into account.

As Petr says, a PEP doesn’t need to be a complete design document. But where it does include specific details, they should be the right details.

Disabling a branch event after its first firing will make it useless. If I only get low impact monitoring by disabling the event, then I won’t have low-impact branch coverage. Is this OK?

Maybe I’m misunderstanding the centrality of this idea.

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