prepare selector compute

[zouyee]

Signed-off-by: zounengren zouyee1989@gmail.com

Please provide a description of this PR:
ServiceSelectorCache is a cache of service selectors to avoid high CPU consumption caused by frequent calls to AsSelectorPreValidated

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[howardjohn]

instead of catching the selector would it be simpler to just re-implement the selector using the map directly? It should be fairly simple and avoid the cost.

A bit worried about complexity here.

[zouyee]

instead of catching the selector would it be simpler to just re-implement the selector using the map directly? It should be fairly simple and avoid the cost.

A bit worried about complexity here.

This method has been well practiced in the endpont controller of k8s.

[howardjohn]

This method has been well practiced in the endpont controller of k8s.

I don't think that is a convincing argument to do this on its own. Is there a technical reason this complexity is justified compared to just using the map directly?

[hzxuzhonghu]

Not sure have you tested the performance? Which function call is CPU costing?

[hzxuzhonghu]

/hold

[hzxuzhonghu]

This is heavily increasing memory cost

[zouyee]

original getPodServices:

BenchmarkGetPodServices-8   	    2607	    385935 ns/op	  161913 B/op	    4023 allocs/op

current GetPodServiceMemberships which use ServiceSelectorCache

BenchmarkGetPodServiceMemberships-8   	    4287	    268554 ns/op	   49981 B/op	    1023 allocs/op

more than 50% performance improvement

[hzxuzhonghu]

You have to weigh off cpu and memory. It is not justice to say only CPU

[howardjohn]

Please also compare it to just using the map directly.

[istio-testing]

@zouyee: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
release-notes_istio	c7b450f	link	true	/test release-notes_istio

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[istio-policy-bot]

🚧 This issue or pull request has been closed due to not having had activity from an Istio team member since 2022-06-29. If you feel this issue or pull request deserves attention, please reopen the issue. Please see this wiki page for more information. Thank you for your contributions.

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