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test(ddsketch): add microbenchmarks for add/encode/collapse#2125

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test(ddsketch): add microbenchmarks for add/encode/collapse#2125
gh-worker-dd-mergequeue-cf854d[bot] merged 3 commits into
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yannham/microbenches-ddsketch

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@yannham

@yannham yannham commented Jun 16, 2026

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What does this PR do?

Adds microbenchmarks to libdd-ddsketch, which didn't have any. Covers the operations on the hot trace-stats / metrics-aggregation path and the IPC/stats export path:

  • add / add_with_count across deterministic latency distributions: clustered_near_zero (~1us..1ms), large_values (~1ms..10s), mixed (1us..1s pseudo-shuffled), and a collapsing distribution whose spread exceeds max_size (2048 bins) to exercise the otherwise-unhit low-bin collapse path.
  • encoding
  • ordered_bins / count O(n-bins) read paths used on metrics export.

Motivation

DDSketch::add runs in a tight per-value loop for trace stats and metric aggregation; the interesting cost is LogMapping::index() float math plus VecDeque growth and low-bin collapse. With no benchmarks, there was nothing to catch regressions or drive perf work on this hot path.

How to test the change?

cargo bench -p libdd-ddsketch --no-run            # benches compile
cargo bench -p libdd-ddsketch                     # full run
# quick smoke run:
cargo bench -p libdd-ddsketch -- --warm-up-time 1 --measurement-time 1 --sample-size 10

🤖 Generated with Claude Code, 🤷‍♂️ reviewed by a human

`libdd-ddsketch` had zero benchmarks. Add criterion microbenchmarks
covering the hot and export paths:

- `add` / `add_with_count` across deterministic latency distributions
  (clustered, large, mixed) plus a wide-spread distribution that forces
  the store past `max_size` (2048) to exercise low-bin collapse.
- `into_pb` / `encode_to_vec` protobuf serialization, seeded across
  distributions that vary the populated bin-vector length.
- `ordered_bins` / `count` O(n-bins) read paths used on metrics export.

Wires up `[dev-dependencies] criterion`, an explicit `[[bench]]` entry
with `harness = false`, and `autobenches = false` (mirroring
`libdd-sampling`).

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
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Clippy Allow Annotation Report

Comparing clippy allow annotations between branches:

  • Base Branch: origin/main
  • PR Branch: origin/yannham/microbenches-ddsketch

Summary by Rule

Rule Base Branch PR Branch Change

Annotation Counts by File

File Base Branch PR Branch Change

Annotation Stats by Crate

Crate Base Branch PR Branch Change
clippy-annotation-reporter 5 5 No change (0%)
datadog-ffe-ffi 1 1 No change (0%)
datadog-ipc 21 21 No change (0%)
datadog-live-debugger 4 4 No change (0%)
datadog-live-debugger-ffi 10 10 No change (0%)
datadog-profiling-replayer 4 4 No change (0%)
datadog-sidecar 46 46 No change (0%)
libdd-common 13 13 No change (0%)
libdd-common-ffi 12 12 No change (0%)
libdd-data-pipeline 5 5 No change (0%)
libdd-ddsketch 2 2 No change (0%)
libdd-dogstatsd-client 1 1 No change (0%)
libdd-profiling 13 13 No change (0%)
libdd-remote-config 3 3 No change (0%)
libdd-telemetry 20 20 No change (0%)
libdd-tinybytes 4 4 No change (0%)
libdd-trace-normalization 2 2 No change (0%)
libdd-trace-obfuscation 3 3 No change (0%)
libdd-trace-stats 1 1 No change (0%)
libdd-trace-utils 12 12 No change (0%)
Total 182 182 No change (0%)

About This Report

This report tracks Clippy allow annotations for specific rules, showing how they've changed in this PR. Decreasing the number of these annotations generally improves code quality.

@datadog-prod-us1-5

datadog-prod-us1-5 Bot commented Jun 16, 2026

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Tests

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
Patch Coverage: 100.00%
Overall Coverage: 73.36% (+0.29%)

This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 87d8ba8 | Docs | Datadog PR Page | Give us feedback!

@dd-octo-sts

dd-octo-sts Bot commented Jun 16, 2026

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Artifact Size Benchmark Report

aarch64-alpine-linux-musl
Artifact Baseline Commit Change
/aarch64-alpine-linux-musl/lib/libdatadog_profiling.a 83.67 MB 83.67 MB 0% (0 B) 👌
/aarch64-alpine-linux-musl/lib/libdatadog_profiling.so 7.70 MB 7.70 MB 0% (0 B) 👌
aarch64-unknown-linux-gnu
Artifact Baseline Commit Change
/aarch64-unknown-linux-gnu/lib/libdatadog_profiling.so 10.34 MB 10.34 MB 0% (0 B) 👌
/aarch64-unknown-linux-gnu/lib/libdatadog_profiling.a 94.77 MB 94.77 MB 0% (0 B) 👌
libdatadog-x64-windows
Artifact Baseline Commit Change
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.dll 24.83 MB 24.83 MB 0% (0 B) 👌
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.lib 87.33 KB 87.33 KB 0% (0 B) 👌
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.pdb 180.86 MB 180.86 MB 0% (0 B) 👌
/libdatadog-x64-windows/debug/static/datadog_profiling_ffi.lib 925.02 MB 925.02 MB 0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.dll 8.09 MB 8.09 MB 0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.lib 87.33 KB 87.33 KB 0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.pdb 23.94 MB 23.94 MB 0% (0 B) 👌
/libdatadog-x64-windows/release/static/datadog_profiling_ffi.lib 47.78 MB 47.78 MB 0% (0 B) 👌
libdatadog-x86-windows
Artifact Baseline Commit Change
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.dll 21.52 MB 21.52 MB 0% (0 B) 👌
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.lib 88.71 KB 88.71 KB 0% (0 B) 👌
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.pdb 184.87 MB 184.87 MB 0% (0 B) 👌
/libdatadog-x86-windows/debug/static/datadog_profiling_ffi.lib 917.97 MB 917.97 MB 0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.dll 6.24 MB 6.24 MB 0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.lib 88.71 KB 88.71 KB 0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.pdb 25.66 MB 25.66 MB 0% (0 B) 👌
/libdatadog-x86-windows/release/static/datadog_profiling_ffi.lib 45.41 MB 45.41 MB 0% (0 B) 👌
x86_64-alpine-linux-musl
Artifact Baseline Commit Change
/x86_64-alpine-linux-musl/lib/libdatadog_profiling.a 74.59 MB 74.59 MB 0% (0 B) 👌
/x86_64-alpine-linux-musl/lib/libdatadog_profiling.so 8.58 MB 8.58 MB 0% (0 B) 👌
x86_64-unknown-linux-gnu
Artifact Baseline Commit Change
/x86_64-unknown-linux-gnu/lib/libdatadog_profiling.a 90.01 MB 90.01 MB 0% (0 B) 👌
/x86_64-unknown-linux-gnu/lib/libdatadog_profiling.so 10.44 MB 10.44 MB 0% (0 B) 👌

yannham and others added 2 commits June 16, 2026 15:59
Replace the index-derived pseudo-distributions (an LCG-style hash for
`mixed`, `i % x` arithmetic elsewhere) with samples drawn from a
seeded `rand_chacha::ChaCha8Rng`. ChaCha's algorithm is stable across
`rand` releases (unlike `StdRng`), so runs stay reproducible. Values
are pre-generated into an array before timing so sampling cost is
excluded from the measured loop. The `Distribution` type and named
generator functions are kept.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
@yannham
yannham marked this pull request as ready for review June 16, 2026 15:45
@yannham
yannham requested review from a team as code owners June 16, 2026 15:45
@gh-worker-dd-mergequeue-cf854d
gh-worker-dd-mergequeue-cf854d Bot merged commit 952c2ef into main Jun 16, 2026
108 of 111 checks passed
@gh-worker-dd-mergequeue-cf854d
gh-worker-dd-mergequeue-cf854d Bot deleted the yannham/microbenches-ddsketch branch June 16, 2026 17:06
iunanua added a commit that referenced this pull request Jul 7, 2026
…ibdd-data-pipeline, libdd-li... (#2201)

# Release proposal for libdd-capabilities-impl, libdd-common,
libdd-data-pipeline, libdd-library-config, libdd-remote-config,
libdd-sampling, libdd-telemetry, libdd-tinybytes, libdd-trace-utils and
their dependencies

This PR contains version bumps based on public API changes and commits
since last release.

## libdd-capabilities
**Next version:** `2.1.0`
**Semver bump:** `minor`
**Tag:** `libdd-capabilities-v2.1.0`

### Commits

- feat(data-pipeline)!: add stdout log trace exporter (#2074)

## libdd-common
**Next version:** `5.1.0`
**Semver bump:** `minor`
**Tag:** `libdd-common-v5.1.0`

### Commits

- refactor(clippy): prefer core and alloc imports (#2196)
- fix: update rustls-webpki to 0.103.13 (#2187)
- fix: update anyhow for unsoundness (#2186)
- feat(machine id): Add helpers in ddcommon to fetch the machine UUID l…
(#2163)

## libdd-ddsketch
**Next version:** `1.1.0`
**Semver bump:** `minor`
**Tag:** `libdd-ddsketch-v1.1.0`

### Commits

- feat(data-pipeline)!: export client-computed span stats as OTLP trace
metrics (#2067)
- test(ddsketch): add microbenchmarks for add/encode/collapse (#2125)

## libdd-trace-protobuf
**Next version:** `4.0.0`
**Semver bump:** `major`
**Tag:** `libdd-trace-protobuf-v4.0.0`

### Commits

- chore!: update protobufs to be in sync with datadog-agent (#2180)
- feat(stats)!: add whole key cardinality limit (#2158)
- feat(remote-config)!: use the proto file from the agent (#2165)
- feat(data-pipeline): OTLP HTTP/protobuf trace export (#2115)

## libdd-capabilities-impl
**Next version:** `3.0.0`
**Semver bump:** `major`
**Tag:** `libdd-capabilities-impl-v3.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.1.0 → ^5.1.0

### Commits

- feat(data-pipeline)!: add stdout log trace exporter (#2074)

## libdd-library-config
**Next version:** `3.0.0`
**Semver bump:** `major`
**Tag:** `libdd-library-config-v3.0.0`

### ⚠️ major bump forced due to:

- `libdd-trace-protobuf`: ^3.0.2 → ^4.0.0

### Commits

- refactor(clippy): prefer core and alloc imports (#2196)
- feat(library-config)!: caller-supplied threadlocal schema and extra
process-context attributes (#2162)
- fix(otel-thread-ctx): put the threadlocal attributes at the right
place in the context (#2167)

## libdd-remote-config
**Next version:** `2.0.0`
**Semver bump:** `major`
**Tag:** `libdd-remote-config-v2.0.0`

### ⚠️ major bump forced due to:

- `libdd-trace-protobuf`: ^3.0.2 → ^4.0.0

### Commits

- refactor(libdd-remote-config)!: hide Target inner properties so they
are not leaked (#2182)
- feat(remote-config)!: use the proto file from the agent (#2165)
- refactor(rc): reexport Endpoint and Tag common types (#2147)

## libdd-trace-normalization
**Next version:** `3.0.0`
**Semver bump:** `major`
**Tag:** `libdd-trace-normalization-v3.0.0`

### ⚠️ major bump forced due to:

- `libdd-trace-protobuf`: ^3.0.1 → ^4.0.0

### Commits

- feat(data-pipeline)!: CSS Trace Filters (#1985)

## libdd-shared-runtime
**Next version:** `2.0.0`
**Semver bump:** `major`
**Tag:** `libdd-shared-runtime-v2.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.1.0 → ^5.1.0

### Commits

- feat(shared-runtime)!: SharedRuntime Borrowed & Owned mode (#2061)
- feat(shared-runtime)!: use weak waker in trigger [APMSP-3371] (#2050)

## libdd-trace-utils
**Next version:** `9.0.0`
**Semver bump:** `major`
**Tag:** `libdd-trace-utils-v9.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.2.0 → ^5.1.0
- `libdd-trace-protobuf`: ^3.0.2 → ^4.0.0

### Commits

- ci(miri): skip slow miri tests (#2188)
- chore!: update protobufs to be in sync with datadog-agent (#2180)
- feat(data-pipeline): add agentless export (#2081)
- feat(data-pipeline)!: add stdout log trace exporter (#2074)
- feat(data-pipeline): OTLP HTTP/protobuf trace export (#2115)
- feat(otlp)!: Export OTLP spans with attribute-level OTel compatibility
(#2091)
- test(trace-utils): add V05 msgpack decode microbenchmark (#2127)
- feat(data-pipeline)!: export client-computed span stats as OTLP trace
metrics (#2067)
- test(trace-utils): add VecMap microbenchmarks (#2126)
- chore(stats)!: submit p0 telemetry in stats (#2130)
- refactor(change-buffer)!: replace slot index with span_id, fix segment
isolation (#2105)
- feat(data-pipeline)!: CSS Trace Filters (#1985)
- feat(trace-exporter): add v1 span and its encoder (#2039)
- fix(trace-utils): mark decoded span maps as deduped (#2110)
- feat(trace-utils)!: change buffer implementation (#2055)
- feat(native-spans)!: change buffer foundation (#2046)
- refactor(span)!: use VecMap for `meta`, `metrics` and `meta_struct`
for v04 spans (#2043)
- test: fix timeouts on heavily contended scenarios (#2093)

## libdd-telemetry
**Next version:** `6.0.0`
**Semver bump:** `major`
**Tag:** `libdd-telemetry-v6.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.2.0 → ^5.1.0
- `libdd-shared-runtime`: ^1.0.0 → ^2.0.0

### Commits

- ci(miri): skip slow miri tests (#2188)
- refactor(libdd-telemetry)!: avoid leaking libdd-common types in the
public API (#2152)
- feat(shared-runtime)!: SharedRuntime Borrowed & Owned mode (#2061)

## libdd-trace-obfuscation
**Next version:** `5.0.0`
**Semver bump:** `major`
**Tag:** `libdd-trace-obfuscation-v5.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.2.0 → ^5.1.0
- `libdd-trace-protobuf`: ^3.0.2 → ^4.0.0
- `libdd-trace-utils`: ^8.0.0 → ^9.0.0

### Commits

- refactor(clippy): prefer core and alloc imports (#2196)
- ci(miri): skip slow miri tests (#2188)
- fix: update anyhow for unsoundness (#2186)

## libdd-trace-stats
**Next version:** `6.0.0`
**Semver bump:** `major`
**Tag:** `libdd-trace-stats-v6.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.2.0 → ^5.1.0
- `libdd-shared-runtime`: ^1.0.0 → ^2.0.0
- `libdd-trace-protobuf`: ^3.0.2 → ^4.0.0
- `libdd-trace-utils`: ^8.0.0 → ^9.0.0

### Commits

- chore!: update protobufs to be in sync with datadog-agent (#2180)
- feat(stats)!: send telemetry for cardinality limits (#2159)
- feat(stats)!: add whole key cardinality limit (#2158)
- fix(trace-stats)!: add grpc_method to aggregation key (#2151)
- feat(shared-runtime)!: SharedRuntime Borrowed & Owned mode (#2061)
- feat(data-pipeline)!: export client-computed span stats as OTLP trace
metrics (#2067)
- refactor(span)!: use VecMap for `meta`, `metrics` and `meta_struct`
for v04 spans (#2043)

## libdd-data-pipeline
**Next version:** `7.0.0`
**Semver bump:** `major`
**Tag:** `libdd-data-pipeline-v7.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.2.0 → ^5.1.0
- `libdd-shared-runtime`: ^1.0.0 → ^2.0.0
- `libdd-telemetry`: ^5.0.1 → ^6.0.0
- `libdd-trace-protobuf`: ^3.0.2 → ^4.0.0
- `libdd-trace-stats`: ^5.0.0 → ^6.0.0
- `libdd-trace-utils`: ^8.0.0 → ^9.0.0

### Commits

- feat(trace_exporter): enable telemetry in stats exporter (#2160)
- refactor(libdd-telemetry)!: avoid leaking libdd-common types in the
public API (#2152)
- feat(stats): emit canonical gRPC status name for OTLP
rpc.response.status_code (#2183)
- feat(data-pipeline): add agentless export (#2081)
- feat(stats)!: send telemetry for cardinality limits (#2159)
- feat(stats)!: add whole key cardinality limit (#2158)
- fix(trace-stats)!: add grpc_method to aggregation key (#2151)
- feat(data-pipeline)!: add stdout log trace exporter (#2074)
- feat(shared-runtime)!: SharedRuntime Borrowed & Owned mode (#2061)
- feat(data-pipeline): OTLP HTTP/protobuf trace export (#2115)
- feat(otlp)!: Export OTLP spans with attribute-level OTel compatibility
(#2091)
- feat(data-pipeline)!: export client-computed span stats as OTLP trace
metrics (#2067)
- chore(stats)!: submit p0 telemetry in stats (#2130)
- feat(data-pipeline)!: CSS Trace Filters (#1985)
- feat(shared-runtime)!: use weak waker in trigger [APMSP-3371] (#2050)
- refactor(span)!: use VecMap for `meta`, `metrics` and `meta_struct`
for v04 spans (#2043)
- feat(stats)!: add endpoint gating to client-side stats [APMSP-3361]
(#2040)

## libdd-dogstatsd-client
**Next version:** `4.0.0`
**Semver bump:** `major`
**Tag:** `libdd-dogstatsd-client-v4.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.1.0 → ^5.1.0


## libdd-sampling
**Next version:** `5.0.0`
**Semver bump:** `major`
**Tag:** `libdd-sampling-v5.0.0`

### ⚠️ major bump forced due to:

- `libdd-common`: ^4.2.0 → ^5.1.0
- `libdd-trace-utils`: ^8.0.0 → ^9.0.0


[APMSP-3371]:
https://datadoghq.atlassian.net/browse/APMSP-3371?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: iunanua <[email protected]>
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