Cloning a histogram with `structuredClone()` or `postMessage()` shares
the native histogram instead of copying it. Capturing the state of a
histogram at a point in time, while other code keeps recording into
it, requires serializing it with `export()` and parsing the result
with `importHistogram()`.
Add `histogram.snapshot()`, which returns a new, independent
`Histogram` containing a copy of the histogram's configuration,
recorded values, `exceeds` count, and EWMA state, without the
serialization round trip. Values cannot be recorded into the returned
histogram. The method is available on all histograms, including
`RecordableHistogram` and `ELDHistogram` instances.
Signed-off-by: James M Snell <jasnell@gmail.com>
Assisted-by: OpenCode
PR-URL: https://github.com/nodejs/node/pull/66099
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
`performance.nodeTiming.uvMetricsInfo` returns the libuv event loop
metrics as numbers, which are only exact up to
`Number.MAX_SAFE_INTEGER`. Add `uvMetricsInfoBigInt`, which returns
the same metrics as bigints backed by `uint64_t` storage, carrying the
full 64-bit range reported by libuv.
A single native call fills both a `Float64Array` and a
`BigUint64Array`, so `uvMetricsInfo` does not pay for bigint
allocation and conversion. The new property is omitted from
`toJSON()`, as `JSON.stringify()` cannot serialize bigints.
Assisted-by: OpenCode
Signed-off-by: James M Snell <jasnell@gmail.com>
PR-URL: https://github.com/nodejs/node/pull/66094
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
The current recordable `Histogram` does not maintain any sense
of time. Samples accumulate indefinitely as they are collected.
This implements a relatively simple sliding-window mechanism
that can be count or time based. The key benefit is that the
window remains fixed/bounded while samples are recorded.
The sliding window is chunk based. Internally, it maintains
a ring buffer of a fixed number of individual histograms.
When snapshot() is called, those are materialized into a
single combined histogram. As the window slides, older
chunks (and all of the samples they hold) are dropped from
the window so the window drops however many samples happened
to be in that chunk. This does mean that precision of the
window is determined by the chunk size.
Signed-off-by: James M Snell <jasnell@gmail.com>
Assisted-by: Opencode
PR-URL: https://github.com/nodejs/node/pull/65825
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Implements quantile-respectful density estimate calcuation
on Histogram. Helps with tail-focused latency analysis
without retaining raw samples.
Baking this directly into Node.js, based on a 1 million
sample, 1k bin workload, this impl is roughly 150-325x
faster than performing the equivalent in Rscript.
Signed-off-by: James M Snell <jasnell@gmail.com>
Assisted-by: Opencode
PR-URL: https://github.com/nodejs/node/pull/65806
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
* Update the user timing implementation to conform to
User Timing Level 3.
* Reimplement user timing and timerify with pure JavaScript
implementations
* Simplify the C++ implementation for gc and http2 perf
* Runtime deprecate additional perf entry properties
in favor of the standard detail argument
* Disable the `buffered` option on PerformanceObserver,
all entries are queued and dispatched on setImmediate.
Only entries with active observers are buffered.
* This does remove the user timing and timerify
trace events. Because the trace_events are still
considered experimental, those can be removed without
a deprecation cycle. They are removed to improve
performance and reduce complexity.
Old: `perf_hooks/usertiming.js n=100000: 92,378.01249733355`
New: perf_hooks/usertiming.js n=100000: 270,393.5280638482`
PR-URL: https://github.com/nodejs/node/pull/37136
Refs: https://github.com/nodejs/diagnostics/issues/464
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Use uv_metrics_idle_time() to return a high resolution millisecond timer
of the amount of time the event loop has been idle since it was
initialized.
Include performance.eventLoopUtilization() API to handle the math of
calculating the idle and active times. This has been added to prevent
accidental miscalculations of the event loop utilization. Such as not
taking into consideration offsetting nodeTiming.loopStart or timing
differences when being called from a Worker thread.
PR-URL: https://github.com/nodejs/node/pull/34938
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Adrian Estrada <edsadr@gmail.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>
Rafael Gonzaga