The Go runtime/metrics package currently exports extremely granular
histograms. Exponentially bucket any histogram with unit "seconds"
or "bytes" instead to dramatically reduce the number of buckets, and
thus the number of metrics.
This change also adds a test to check for expected cardinality to
prevent cardinality surprises in the future.
Signed-off-by: Michael Anthony Knyszek <mknyszek@google.com>
A previous PR made it so that the Go 1.17 collector locked only around
uses of rmSampleBuf, but really that means that Metric values may be
sent over the channel containing some values from future metrics.Read
calls. While generally-speaking this isn't a problem, we lose any
consistency guarantees provided by the runtime/metrics package.
Also, that optimization to not just lock around all of Collect was
premature. Truthfully, Collect is called relatively infrequently, and
its critical path is fairly fast (10s of µs). To prove it, this change
also adds a benchmark.
name old time/op new time/op delta
GoCollector-16 43.7µs ± 2% 43.2µs ± 2% ~ (p=0.190 n=9+9)
Note that because the benchmark is single-threaded it actually looks
like it might be getting *slightly* faster, because all those Collect
calls for the Metrics are direct calls instead of interface calls.
Signed-off-by: Michael Anthony Knyszek <mknyszek@google.com>
* Check validity of method and code label values
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Use more flexibly functional option pattern for configuration
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Update documentation
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Simplify
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Fix inconsistent method naming
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
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>
Current structs for v1 HTTP API assume that there is chunkCount and timeSeriesCount on /api/v1/status/runtimeinfo, which seems to be gone for at least a few releases. /api/v1/status/tsdb now holds an extra headStats block with chunkCount, numSeries and a few other fields.
Update API models and tests to reflect this change.
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
This function calculates exponential buckets with different arguments
than the existing ExponentialBuckets function. Instead of specifying the
start and factor, the user can specify the min and max bucket value. We
have been doing it this way internally at my company for some time.
Signed-off-by: Seth Bunce <seth.bunce@getcruise.com>
This seem what OTel is converging towards, see
https://github.com/open-telemetry/oteps/pull/149 .
I see pros and cons with base-10 vs base-2. They are discussed in
detail in that OTel PR, and the gist of the discussion is pretty much
in line with my design doc. Since the balance is easy to tip here, I
think we should go with base-2 if OTel picks base-2. This also seems
to be in agreement with several proprietary solution (see again the
discussion on that OTel PR.)
The idea to make the number of buckets per power of 2 (or formerly 10)
a power of 2 itself was also sketched out in the design doc
already. It guarantees mergeability of different resolutions. I was
undecided between making it a recommendation or mandatory. Now I think
it should be mandatory as it has the additional benefit of playing
well with OTel's plans.
This commit also addresses a number of outstanding TODOs.
Signed-off-by: beorn7 <beorn@grafana.com>
beorn7