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callcount

sync.Once.Do

standard library

The 213th most-called standard-library method by production calls. Called 9,710 times across 686 modules; 4,628 of those run outside tests and generated code.

All of sync → Docs on pkg.go.dev ↗

prod calls
4,628
non-test, non-generated
all calls
9,710
total callsites
modules
686
distinct callers
in loop
3%
of prod calls
in tests
11%
1,077 calls
resolved
100%
to a known target

resolution mix

How each call resolves

How each call was attributed. Only resolved kinds, where the target function is known, count toward the ranking. Interface dispatch and unresolved receivers are reported separately and never guessed. Read the taxonomy →

  • Concrete method99%A method on a value whose type is known exactly.
  • Embedded method<1%Reached through an embedded type.

estimate

Experimental

Estimated relative cost

Roughly 0.00× the estimated relative cost of fmt.Sprintf . Benchmarked at 1.98 ns/op × 4,628 production calls, normalized so fmt.Sprintf = 1.0.

This is not dollars and not a verdict. Per-op time depends heavily on inputs (argument sizes, contention, patterns), the benchmark ran on a single machine (darwin/arm64 (Apple Silicon), go1.26.0), and static call counts are not runtime frequency. How this is estimated →

who calls this

Notable callers

Production calls into Once.Do from notable Go projects. Open one on the map to see what else it hammers.

where it's called

Callsites in the wild

12 representative callsites of 9,710, prioritizing in-loop and non-test usage. We link to source, never display it.

Once.Do · 12 of 9,710 callsites

top callers

The modules that reach for it

The modules that call Once.Do most in this snapshot.

  • github.com/yandex-cloud/go-genproto93210%
  • google.golang.org/genproto6607%
  • github.com/envoyproxy/go-control-plane/envoy5996%
  • github.com/kubernetes/kubernetes2743%
  • github.com/slack-go/slack1742%

siblings

More from sync

The other most-called members in this package. See all →