Commit Graph

2 Commits

Author SHA1 Message Date
Michael Knyszek 772b89389c Make the Go 1.17 collector thread-safe (#969) 2022-05-13 10:33:54 +02:00
Michael Knyszek 22da9497b8
Use the runtime/metrics package for the Go collector for 1.17+ (#955)
This change introduces use of the runtime/metrics package in place of
runtime.MemStats for Go 1.17 or later. The runtime/metrics package was
introduced in Go 1.16, but not all the old metrics were accounted for
until 1.17.

The runtime/metrics package offers several advantages over using
runtime.MemStats:
* The list of metrics and their descriptions are machine-readable,
  allowing new metrics to get added without any additional work.
* Detailed histogram-based metrics are now available, offering much
  deeper insights into the Go runtime.
* The runtime/metrics API is significantly more efficient than
  runtime.MemStats, even with the additional metrics added, because
  it does not require any stop-the-world events.

That being said, integrating the package comes with some caveats, some
of which were discussed in #842. Namely:
* The old MemStats-based metrics need to continue working, so they're
  exported under their old names backed by equivalent runtime/metrics
  metrics.
* Earlier versions of Go need to continue working, so the old code
  remains, but behind a build tag.

Finally, a few notes about the implementation:
* This change includes a whole bunch of refactoring to avoid significant
  code duplication.
* This change adds a new histogram metric type specifically optimized
  for runtime/metrics histograms. This type's methods also include
  additional logic to deal with differences in bounds conventions.
* This change makes a whole bunch of decisions about how runtime/metrics
  names are translated.
* This change adds a `go generate` script to generate a list of expected
  runtime/metrics names for a given Go version for auditing. Users of
  new versions of Go will transparently be allowed to use new metrics,
  however.

Signed-off-by: Michael Anthony Knyszek <mknyszek@google.com>
2022-01-16 16:41:56 +00:00