Perf framework: align with .NET Azure.Test.Perf

[Jinming-Hu]

Summary

Brings the C++ perf framework (sdk/core/perf) and the Storage Blobs perf
tests to format / contract parity with the .NET Azure.Test.Perf reference,
which the cross-language perf-automation pipeline keys off.

This is purely a perf-harness / engineering-system change. No public SDK
surface is touched and external customers shouldn't notice it — there is
intentionally no customer-facing CHANGELOG entry.

Framework changes (sdk/core/perf)

• Latency distribution (latency_stats.{hpp,cpp}): per-op collector
  emitting the .NET 8-percentile distribution (50 / 75 / 90 / 99 / 99.9 /
  99.99 / 99.999 / 100) with the exact === Latency Distribution ===
  header and {pct,7:N3}% {ms,8:N2}ms row format.
• CPU + memory sampler (process_stats.{hpp,cpp}): the throughput
  Completed N operations ... (Y ops/s, Z s/op, P% CPU) line now
  includes inline CPU like .NET, while preserving the existing
  (... ops/s substring downstream Cpp.cs regex relies on.
• Result output (result_output.{hpp,cpp}):
  • --results-file writes
    [{ "Time": <ms>, "Size": <bytes> }, ...] matching .NET
    OperationResult schema (PascalCase, Size = -1 when the test
    has no SizeOptions).
  • --statistics / --job-statistics wraps a BenchmarkOutput
    envelope between #StartJobStatistics and #EndJobStatistics
    with Metadata before Measurements (key order matches .NET).
  • Timestamps emitted at 100-nanosecond (7-digit) resolution like
    .NET DateTime.ToString("O").
• New options matching .NET PerfOptions:
  --status-interval, --results-file, --sync.
• Non-breaking CLI aliases matching .NET names:
  --job-statistics (bare switch) alongside existing --statistics <0|1>,
  and --no-cleanup (bare switch) alongside existing --noclean <0|1>.

Storage Blob perf tests (sdk/storage/azure-storage-blobs/test/perf)

New blob-test flags aligning the C++ UploadBlob / DownloadBlob /
ListBlob scenarios with the .NET / Go test surface:

• --upload-method (buffer | stream | single)
• --download-method (buffer | stream)
• --block-size, --concurrency, --num-blobs, --page-size

A memory-budget guard (memory_budget.hpp) prevents OOM in buffer-mode
tests at multi-GiB payloads.

Things deliberately not included

• No === Versions === block. .NET's PrintAssemblyVersions prints
  runtime + loaded Azure assembly versions; the natural C++ analogue
  would be the per-test VCPKG_*_VERSION lines that the storage perf
  test already emits independently. A separate compiler-info module added
  no value and isn't faithful to .NET, so it's omitted.
• No CHANGELOG entry — perf harness is internal.

Verification

Built MinSizeRel on Windows / VS 2026 with vcpkg x64-windows-static
(curl, openssl, gtest, opentelemetry-cpp). All 9 perf unit tests pass.
A live perf run against a storage account using AzureCliCredential
produced output that diffs byte-clean against an equivalent
Azure.Storage.Blobs.Perf .NET run for every contract emitted by this
change: latency-distribution header / rows, throughput line shape
(including % CPU), BenchmarkOutput JSON shape and key order,
timestamp precision, and results-file schema.

[Copilot]

Pull request overview

This PR aligns the C++ perf harness (sdk/core/perf) and Storage Blobs perf scenarios with the output/CLI contract expected by cross-language perf automation (modeled after .NET Azure.Test.Perf), including standardized job-statistics/results-file outputs plus CPU/memory and latency reporting.

Changes:

• Add per-operation latency collection with .NET-compatible percentile distribution output and optional per-op results-file JSON ({Time, Size}).
• Add always-on process CPU% and resident-memory sampling, surfacing metrics in live status lines and the final throughput line.
• Update Storage Blobs perf scenarios/options to match cross-language flags (upload/download methods, paging, chunk size, concurrency) and introduce a memory-budget guard header.

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
sdk/storage/azure-storage-blobs/test/perf/inc/azure/storage/blobs/test/upload_blob_test.hpp	Adds upload-method variants and forwards block-size/concurrency; adds memory-budget guard usage.
sdk/storage/azure-storage-blobs/test/perf/inc/azure/storage/blobs/test/memory_budget.hpp	New cross-platform “fail fast” memory budget guard for buffer-mode perf tests.
sdk/storage/azure-storage-blobs/test/perf/inc/azure/storage/blobs/test/list_blob_test.hpp	Adds --num-blobs aliasing and --page-size support for ListBlobs.
sdk/storage/azure-storage-blobs/test/perf/inc/azure/storage/blobs/test/download_blob_test.hpp	Adds download-method variants, forwarding of block-size/concurrency, and memory-budget guard usage.
sdk/storage/azure-storage-blobs/test/perf/CMakeLists.txt	Adds the new memory budget header to the perf test target inputs.
sdk/storage/azure-storage-blobs/perf-tests.yml	Extends perf matrix to exercise new upload/download/list flags (streaming, chunk/concurrency, paging).
sdk/core/perf/test/src/result_output_test.cpp	New unit tests for --results-file JSON shape and job-statistics envelope ordering.
sdk/core/perf/test/src/process_stats_test.cpp	New unit tests for process sampler start/stop/reset.
sdk/core/perf/test/src/latency_stats_test.cpp	New unit tests for percentile computation, grouping, reset, and concurrent record.
sdk/core/perf/test/CMakeLists.txt	Adds new perf-framework unit test sources to the test target.
sdk/core/perf/src/result_output.cpp	Implements results-file writer and #StartJobStatistics/#EndJobStatistics output with .NET-like timestamp formatting.
sdk/core/perf/src/program.cpp	Wires in latency collection, process stats sampling, status-interval, results-file emission, and latency distribution printing.
sdk/core/perf/src/process_stats.cpp	Implements cross-platform CPU and RSS sampling for Windows/Linux/macOS.
sdk/core/perf/src/options.cpp	Adds new global options (--status-interval, --results-file) and bare-switch aliases for .NET parity.
sdk/core/perf/src/latency_stats.cpp	Implements latency collector storage and percentile/mean summarization.
sdk/core/perf/src/arg_parser.cpp	Parses new global options and bare-switch aliases into GlobalTestOptions.
sdk/core/perf/inc/azure/perf/result_output.hpp	Declares RunSummary, OperationResult, and result/job-statistics output helpers.
sdk/core/perf/inc/azure/perf/process_stats.hpp	Declares the ProcessStatsSampler API and snapshot types.
sdk/core/perf/inc/azure/perf/options.hpp	Extends GlobalTestOptions with status-interval, results-file, and sync flag.
sdk/core/perf/inc/azure/perf/latency_stats.hpp	Declares the latency collector and percentile summary types.
sdk/core/perf/inc/azure/perf.hpp	Exposes new perf framework components via the top-level convenience header.
sdk/core/perf/CMakeLists.txt	Adds new perf framework headers/sources to the azure-perf library build.

[jalauzon-msft]

Not too familiar with C++ so I did not dig into the implementation much, but overall change looks fine. I did leave some comments as this probably contains more than we need/want but if you want to keep everything, that is also probably fine.

[Jinming-Hu]

Running Azure SDK for C++ Storage Perf Tests

Prereqs

az login
$env:AZURE_STORAGE_ACCOUNT_NAME = "<your-storage-account>"   # token-credential mode
# or, for accounts that allow shared key:
# $env:STORAGE_CONNECTION_STRING = (az storage account show-connection-string -n <acct> -g <rg> --query connectionString -o tsv)

Run all commands from a VS x64 Native Tools prompt (or after vcvars64.bat).
You don't need to install vcpkg — CMake auto-fetches a pinned copy on first
configure (set AZURE_SDK_DISABLE_AUTO_VCPKG=1 to opt out).

Build and run

cd azure-sdk-for-cpp
cmake -G Ninja -B build `
  -DBUILD_TESTING=ON -DBUILD_PERFORMANCE_TESTS=ON `
  -DDISABLE_AZURE_CORE_OPENTELEMETRY=ON -DCMAKE_BUILD_TYPE=MinSizeRel `
  -DVCPKG_TARGET_TRIPLET=x64-windows-static
cmake --build build --target azure-storage-blobs-perf

.\build\sdk\storage\azure-storage-blobs\test\perf\azure-storage-blobs-perf.exe `
    UploadBlob --size 10240 --parallel 4 --warmup 3 --duration 5 `
    --latency 1 --statistics 1 --token-credential

Run with no test name to list available tests (UploadBlob, DownloadBlob, ListBlob, ...).

Useful flags: --size, --parallel, --warmup, --duration, --latency 1, --statistics 1, --results-file out.json, --token-credential, --upload-method buffer|stream|single, --download-method buffer|stream, --block-size, --concurrency, --num-blobs, --page-size.