[lucaspimentel]

Summary of changes

• Make DD_DOTNET_TRACER_HOME optional by deriving the managed tracer's location from the native profiler path when it is unset.
• Keep native-profiler-only tests isolated from the managed SDK, and add production-mode coverage for profiling with tracing disabled.

Reason for change

• Reapply [onboarding] make DD_DOTNET_TRACER_HOME optional in managed loader #7568, which was reverted in Revert "make DD_DOTNET_TRACER_HOME optional in managed loader (#7568)" #7704 after Continuous Profiling integration test failures.
• The fallback exposed unintended SDK startup in profiler-only tests. Explicit component opt-in preserves their isolation without removing the production fallback.

Implementation details

• Prefer an explicit DD_DOTNET_TRACER_HOME, then architecture-specific COR_PROFILER_PATH_* / CORECLR_PROFILER_PATH_*, then the unqualified profiler path. Resolve recognized OS/architecture subdirectories back to the tracer home.
• Keep PROFILER in test loader configs; include TRACER only after explicit opt-in, independently of DD_TRACE_ENABLED.
• Include thread-lifetime samples in the contention-enabled-by-default test to cover blocking threads that may not have their own contention samples.

Test coverage

• Add loader unit tests for explicit overrides, profiler-path fallbacks, platform directories, and missing or whitespace values.
• Exercise tracer instrumentation and smoke tests without DD_DOTNET_TRACER_HOME; add unit coverage for profiler-test component opt-in.
• Add a .NET 6–11 production-mode test that loads both components, disables tracing, and verifies exported profile samples, zero trace requests, and the default managed-activation handshake.
• Before the latest rebase, focused Linux profiler checks passed using reused CI monitoring-home binaries. Negative controls failed as expected when tracing was enabled, managed activation was disabled, or tracer opt-in was removed.
• The full local Linux profiler suite still reports missing ASP.NET Core 3.1, LDAP initialization failures, and socket/exporter errors.

Other details

• Existing explicit tracer-home configurations remain supported.
• Cross-platform CI validation of the latest revision is pending.

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[dd-trace-dotnet-ci-bot]

Execution-Time Benchmarks Report ⏱️

Execution-time results for samples comparing This PR (7767) and master.

✅ No regressions detected

📄 View the full report (charts + all metrics) →

[andrewlock]

LGTM (assuming direct revert, I didn't re-review) as long as you've done an "all products" run in CI 🙂

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-10-26 20:29:16

Comparing candidate commit aff747b in PR branch lpimentel/remove-tracer-home-dependency-redux with baseline commit 5f97650 in branch master.

📊 Benchmarking dashboard

Found 0 performance improvements and 0 performance regressions! Performance is the same for 72 metrics, 0 unstable metrics, 10 known flaky benchmarks, 116 flaky benchmarks without significant changes.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

Known flaky benchmarks

These benchmarks are marked as flaky and will not trigger a failure. Modify FLAKY_BENCHMARKS_REGEX to control which benchmarks are marked as flaky.

scenario:Benchmarks.Trace.AgentWriterBenchmark.WriteAndFlushEnrichedTraces net6.0

• unstable execution_time [-87.202ms; -25.547ms] or [-17.189%; -5.036%]

scenario:Benchmarks.Trace.AspNetCoreBenchmark.SendRequest net6.0

• unstable execution_time [+27.495ms; +99.730ms] or [+6.141%; +22.275%]

scenario:Benchmarks.Trace.AspNetCoreBenchmark.SendRequest netcoreapp3.1

• unstable execution_time [-58.014ms; +28.711ms] or [-13.789%; +6.824%]

scenario:Benchmarks.Trace.CIVisibilityProtocolWriterBenchmark.WriteAndFlushEnrichedTraces net472

• unstable execution_time [-57.604ms; +2.576ms] or [-10.113%; +0.452%]

scenario:Benchmarks.Trace.CharSliceBenchmark.OptimizedCharSliceWithPool netcoreapp3.1

• unstable execution_time [-262.861µs; -67.355µs] or [-13.696%; -3.509%]
• unstable throughput [+30.325op/s; +155.500op/s] or [+5.818%; +29.833%]

scenario:Benchmarks.Trace.Iast.StringAspectsBenchmark.StringConcatAspectBenchmark net472

• unstable execution_time [-26.708µs; +22.728µs] or [-6.028%; +5.130%]

scenario:Benchmarks.Trace.Iast.StringAspectsBenchmark.StringConcatAspectBenchmark net6.0

• unstable execution_time [-52.474µs; +8.326µs] or [-9.955%; +1.579%]

scenario:Benchmarks.Trace.Iast.StringAspectsBenchmark.StringConcatAspectBenchmark netcoreapp3.1

• 🟥 allocated_mem [+25.981KB; +26.001KB] or [+10.440%; +10.448%]
• unstable execution_time [-478.286µs; -225.954µs] or [-53.567%; -25.306%]
• unstable throughput [+270.868op/s; +627.704op/s] or [+19.073%; +44.200%]

scenario:Benchmarks.Trace.Iast.StringAspectsBenchmark.StringConcatBenchmark netcoreapp3.1

• unstable execution_time [-5.521µs; +0.425µs] or [-9.871%; +0.760%]

scenario:Benchmarks.Trace.SingleSpanAspNetCoreBenchmark.SingleSpanAspNetCore netcoreapp3.1

• 🟩 throughput [+15609027.330op/s; +16021800.889op/s] or [+6.839%; +7.019%]

Known flaky benchmarks without significant changes:

• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_AddEvent_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_AddEvent_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_AddEvent_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_GetContext_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_GetContext_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_GetContext_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_SetAttributes_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_SetAttributes_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_SetAttributes_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_SetStatus_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_SetStatus_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_SetStatus_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_UpdateName_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_UpdateName_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.ActivityBenchmark.StartSpan_UpdateName_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_AddEvent_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_AddEvent_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_AddEvent_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_GetContext_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_GetContext_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_GetContext_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_RecordException_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_RecordException_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_RecordException_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_SetAttributes_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_SetAttributes_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_SetAttributes_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_SetStatus_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_SetStatus_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_SetStatus_Sampled netcoreapp3.1
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_UpdateName_Sampled net472
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_UpdateName_Sampled net6.0
• scenario:Benchmarks.OpenTelemetry.InstrumentedApi.Trace.TelemetrySpanBenchmark.StartSpan_UpdateName_Sampled netcoreapp3.1
• scenario:Benchmarks.Trace.ActivityBenchmark.StartStopWithChild net472
• scenario:Benchmarks.Trace.ActivityBenchmark.StartStopWithChild net6.0
• scenario:Benchmarks.Trace.ActivityBenchmark.StartStopWithChild netcoreapp3.1
• scenario:Benchmarks.Trace.AgentWriterBenchmark.WriteAndFlushEnrichedTraces net472
• scenario:Benchmarks.Trace.AgentWriterBenchmark.WriteAndFlushEnrichedTraces netcoreapp3.1
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.AllCycleMoreComplexBody net472
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.AllCycleMoreComplexBody net6.0
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.AllCycleMoreComplexBody netcoreapp3.1
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.AllCycleSimpleBody net472
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.AllCycleSimpleBody net6.0
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.AllCycleSimpleBody netcoreapp3.1
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.ObjectExtractorMoreComplexBody net472
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.ObjectExtractorMoreComplexBody net6.0
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.ObjectExtractorMoreComplexBody netcoreapp3.1
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.ObjectExtractorSimpleBody net472
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.ObjectExtractorSimpleBody net6.0
• scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.ObjectExtractorSimpleBody netcoreapp3.1
• scenario:Benchmarks.Trace.Asm.AppSecEncoderBenchmark.EncodeArgs net472
• scenario:Benchmarks.Trace.Asm.AppSecEncoderBenchmark.EncodeArgs net6.0
• scenario:Benchmarks.Trace.Asm.AppSecEncoderBenchmark.EncodeArgs netcoreapp3.1
• scenario:Benchmarks.Trace.Asm.AppSecEncoderBenchmark.EncodeLegacyArgs net472
• scenario:Benchmarks.Trace.Asm.AppSecEncoderBenchmark.EncodeLegacyArgs net6.0
• scenario:Benchmarks.Trace.Asm.AppSecEncoderBenchmark.EncodeLegacyArgs netcoreapp3.1
• scenario:Benchmarks.Trace.Asm.AppSecWafBenchmark.RunWafRealisticBenchmark net472
• scenario:Benchmarks.Trace.Asm.AppSecWafBenchmark.RunWafRealisticBenchmark net6.0
• scenario:Benchmarks.Trace.Asm.AppSecWafBenchmark.RunWafRealisticBenchmark netcoreapp3.1
• scenario:Benchmarks.Trace.Asm.AppSecWafBenchmark.RunWafRealisticBenchmarkWithAttack net472
• scenario:Benchmarks.Trace.Asm.AppSecWafBenchmark.RunWafRealisticBenchmarkWithAttack net6.0
• scenario:Benchmarks.Trace.Asm.AppSecWafBenchmark.RunWafRealisticBenchmarkWithAttack netcoreapp3.1
• scenario:Benchmarks.Trace.AspNetCoreBenchmark.SendRequest net472
• scenario:Benchmarks.Trace.CIVisibilityProtocolWriterBenchmark.WriteAndFlushEnrichedTraces net6.0
• scenario:Benchmarks.Trace.CIVisibilityProtocolWriterBenchmark.WriteAndFlushEnrichedTraces netcoreapp3.1
• scenario:Benchmarks.Trace.CharSliceBenchmark.OptimizedCharSlice net472
• scenario:Benchmarks.Trace.CharSliceBenchmark.OptimizedCharSlice net6.0
• scenario:Benchmarks.Trace.CharSliceBenchmark.OptimizedCharSlice netcoreapp3.1
• scenario:Benchmarks.Trace.CharSliceBenchmark.OptimizedCharSliceWithPool net472
• scenario:Benchmarks.Trace.CharSliceBenchmark.OptimizedCharSliceWithPool net6.0
• scenario:Benchmarks.Trace.CharSliceBenchmark.OriginalCharSlice net472
• scenario:Benchmarks.Trace.CharSliceBenchmark.OriginalCharSlice net6.0
• scenario:Benchmarks.Trace.CharSliceBenchmark.OriginalCharSlice netcoreapp3.1
• scenario:Benchmarks.Trace.ElasticsearchBenchmark.CallElasticsearch net472
• scenario:Benchmarks.Trace.ElasticsearchBenchmark.CallElasticsearch net6.0
• scenario:Benchmarks.Trace.ElasticsearchBenchmark.CallElasticsearch netcoreapp3.1
• scenario:Benchmarks.Trace.ElasticsearchBenchmark.CallElasticsearchAsync net472
• scenario:Benchmarks.Trace.ElasticsearchBenchmark.CallElasticsearchAsync net6.0
• scenario:Benchmarks.Trace.ElasticsearchBenchmark.CallElasticsearchAsync netcoreapp3.1
• scenario:Benchmarks.Trace.GraphQLBenchmark.ExecuteAsync net472
• scenario:Benchmarks.Trace.GraphQLBenchmark.ExecuteAsync net6.0
• scenario:Benchmarks.Trace.GraphQLBenchmark.ExecuteAsync netcoreapp3.1
• scenario:Benchmarks.Trace.ILoggerBenchmark.EnrichedLog net472
• scenario:Benchmarks.Trace.ILoggerBenchmark.EnrichedLog net6.0
• scenario:Benchmarks.Trace.ILoggerBenchmark.EnrichedLog netcoreapp3.1
• scenario:Benchmarks.Trace.Iast.StringAspectsBenchmark.StringConcatBenchmark net472
• scenario:Benchmarks.Trace.Iast.StringAspectsBenchmark.StringConcatBenchmark net6.0
• scenario:Benchmarks.Trace.Log4netBenchmark.EnrichedLog net472
• scenario:Benchmarks.Trace.Log4netBenchmark.EnrichedLog net6.0
• scenario:Benchmarks.Trace.Log4netBenchmark.EnrichedLog netcoreapp3.1
• scenario:Benchmarks.Trace.RedisBenchmark.SendReceive net472
• scenario:Benchmarks.Trace.RedisBenchmark.SendReceive net6.0
• scenario:Benchmarks.Trace.RedisBenchmark.SendReceive netcoreapp3.1
• scenario:Benchmarks.Trace.SerilogBenchmark.EnrichedLog net472
• scenario:Benchmarks.Trace.SerilogBenchmark.EnrichedLog net6.0
• scenario:Benchmarks.Trace.SerilogBenchmark.EnrichedLog netcoreapp3.1
• scenario:Benchmarks.Trace.SingleSpanAspNetCoreBenchmark.SingleSpanAspNetCore net472
• scenario:Benchmarks.Trace.SingleSpanAspNetCoreBenchmark.SingleSpanAspNetCore net6.0
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishScope net472
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishScope net6.0
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishScope netcoreapp3.1
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishSpan net472
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishSpan net6.0
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishSpan netcoreapp3.1
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishTwoScopes net472
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishTwoScopes net6.0
• scenario:Benchmarks.Trace.SpanBenchmark.StartFinishTwoScopes netcoreapp3.1
• scenario:Benchmarks.Trace.TraceAnnotationsBenchmark.RunOnMethodBegin net472
• scenario:Benchmarks.Trace.TraceAnnotationsBenchmark.RunOnMethodBegin net6.0
• scenario:Benchmarks.Trace.TraceAnnotationsBenchmark.RunOnMethodBegin netcoreapp3.1