daemon/combinator: memoize calculated fingerprints (IDs)

[lukedirtwalker]

A profile shows that ID calculation is a big part of the CPU time of the daemon:

Therefore this change memoizes IDs where possible.
Also re-use buffer for fingerprint calculation.
Use slices package for sorting in the combinator.

[jiceatscion]

This change is 

[oncilla]

Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: all files reviewed, 3 unresolved discussions (waiting on @jiceatscion and @lukedirtwalker)

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-- commits line 6 at r1:
s/cominator/combinator

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private/path/combinator/combinator.go line 140 at r1 (raw file):

// take []snet.PathInterface directly.
func fingerprint(interfaces []snet.PathInterface, sumBuf []byte) snet.PathFingerprint {
	h := sha256.New()

suggestion: You could save another couple of allocation by reusing the same hash.Hash

You could bundle the sum buffer and hash.Hash together in one struct for easy passing around

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private/path/combinator/combinator.go line 149 at r1 (raw file):

		}
	}
	return snet.PathFingerprint(h.Sum(sumBuf[:0]))

Add a comment that this is safe because snet.PathFingerprint is underlying type string.

Also, maybe it is worth to create a compiler check that enforces this. If someone changes it to byte slice -> this will go pufff.

[lukedirtwalker]

Reviewable status: 0 of 4 files reviewed, 2 unresolved discussions (waiting on @jiceatscion and @oncilla)

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-- commits line 6 at r1:

Previously, oncilla (Dominik Roos) wrote…

s/cominator/combinator

Done.

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private/path/combinator/combinator.go line 140 at r1 (raw file):

Previously, oncilla (Dominik Roos) wrote…

suggestion: You could save another couple of allocation by reusing the same hash.Hash

You could bundle the sum buffer and hash.Hash together in one struct for easy passing around

Done.

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private/path/combinator/combinator.go line 149 at r1 (raw file):

Previously, oncilla (Dominik Roos) wrote…

Add a comment that this is safe because snet.PathFingerprint is underlying type string.

Also, maybe it is worth to create a compiler check that enforces this. If someone changes it to byte slice -> this will go pufff.

Done.

Added the comment, Don't know how to add the check.

[jiceatscion]

Reviewed 4 of 4 files at r2, all commit messages.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @oncilla)

[oncilla]

Reviewed 4 of 4 files at r2, all commit messages.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @lukedirtwalker)

[oncilla]

Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @lukedirtwalker)

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private/path/combinator/combinator.go line 149 at r1 (raw file):

Previously, lukedirtwalker (Lukas Vogel) wrote…

Done.

Added the comment, Don't know how to add the check.

// This check ensures that the underlying type of the PathFingerprint
// is string. This is required to create a copy of the buffer. If it were
// to be moved to a []byte, we need to change the code to create
// a proper copy.
func checkUnderlyingType[S ~string](s S) bool { panic("") }

var _ = checkUnderlyingType(Fingerprint(""))

[lukedirtwalker]

Reviewable status: 3 of 4 files reviewed, 1 unresolved discussion (waiting on @jiceatscion and @oncilla)

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private/path/combinator/combinator.go line 149 at r1 (raw file):

Previously, oncilla (Dominik Roos) wrote…

// This check ensures that the underlying type of the PathFingerprint
// is string. This is required to create a copy of the buffer. If it were
// to be moved to a []byte, we need to change the code to create
// a proper copy.
func checkUnderlyingType[S ~string](s S) bool { panic("") }

var _ = checkUnderlyingType(Fingerprint(""))

Done.

panic doesn't work ;)

[oncilla]

Reviewed 1 of 27 files at r3.
Reviewable status: 4 of 31 files reviewed, all discussions resolved (waiting on @jiceatscion)

[oncilla]

Reviewed 1 of 1 files at r4, 28 of 28 files at r6, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @lukedirtwalker)

[lukedirtwalker]

Reviewed 1 of 4 files at r2, 1 of 27 files at r3, 19 of 28 files at r6, 12 of 12 files at r7, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @lukedirtwalker)