Add a Continuous Profiler availability check by andrewlock · Pull Request #7534 · DataDog/dd-trace-dotnet

andrewlock · 2025-09-18T14:57:24Z

Summary of changes

Add a checker to decide whether the profiler is available

Reason for change

We are going to be (and are currently) making P/Invoke calls on startup to call the profiler. If the ClrProfiler is not attached, or the CP file is not available (and so P/Invokes are not re-written) then this can cause additional delays.

Implementation details

Add explicit checks for

Unsupported environments
Has the profiler set the "profiler available" env var (only works on Windows right now)
Are we in known unsupported environments (lambda and Azure functions outside of AAS extension)
Is the ClrProfiler attached

Test coverage

If everything still works, this should work

Other details

A blocker for #7287

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chrisnas

LGTM with just a log level question

anna-git · 2025-09-18T15:20:20Z

+        // Now we're into fuzzy territory. The CP is not available in some environments
+        // - AWS Lambda
+        // - Azure Functions where the site extension is _not_ used
+        var isUnsupported = EnvironmentHelpers.IsAwsLambda()


is it ok if it tries logging here? as this ends up there

otherwise there's this beautiful solution 😅

Yeah, I originally used your solution, but I can't use IsServerless() as it excludes too much. Also, this isn't used in the critical config loading paths, so I think it's ok for us to log if we have to 🙂

ok :) also, you probably know already, FrameworkDescription has a static logger field 😅

dd-trace-dotnet-ci-bot · 2025-09-18T17:59:35Z

Execution-Time Benchmarks Report ⏱️

Execution-time results for samples comparing the following branches/commits:

Execution-time benchmarks measure the whole time it takes to execute a program. And are intended to measure the one-off costs. Cases where the execution time results for the PR are worse than latest master results are shown in red. The following thresholds were used for comparing the execution times:

Welch test with statistical test for significance of 5%
Only results indicating a difference greater than 5% and 5 ms are considered.

Note that these results are based on a single point-in-time result for each branch. For full results, see the dashboard.

Graphs show the p99 interval based on the mean and StdDev of the test run, as well as the mean value of the run (shown as a diamond below the graph).

gantt
    title Execution time (ms) FakeDbCommand (.NET Framework 4.8) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Bailout
    This PR (7534) - mean (72ms)  : 71, 73
     .   : milestone, 72,
    master - mean (72ms)  : 71, 73
     .   : milestone, 72,

    section Baseline
    This PR (7534) - mean (68ms)  : 66, 70
     .   : milestone, 68,
    master - mean (68ms)  : 66, 70
     .   : milestone, 68,

    section CallTarget+Inlining+NGEN
    This PR (7534) - mean (1,001ms)  : 977, 1026
     .   : milestone, 1001,
    master - mean (1,003ms)  : 980, 1026
     .   : milestone, 1003,

gantt
    title Execution time (ms) FakeDbCommand (.NET Core 3.1) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Bailout
    This PR (7534) - mean (106ms)  : 105, 107
     .   : milestone, 106,
    master - mean (106ms)  : 105, 107
     .   : milestone, 106,

    section Baseline
    This PR (7534) - mean (105ms)  : 103, 108
     .   : milestone, 105,
    master - mean (105ms)  : 103, 108
     .   : milestone, 105,

    section CallTarget+Inlining+NGEN
    This PR (7534) - mean (707ms)  : 689, 724
     .   : milestone, 707,
    master - mean (714ms)  : 699, 729
     .   : milestone, 714,

gantt
    title Execution time (ms) FakeDbCommand (.NET 6) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Bailout
    This PR (7534) - mean (94ms)  : 93, 95
     .   : milestone, 94,
    master - mean (94ms)  : 93, 95
     .   : milestone, 94,

    section Baseline
    This PR (7534) - mean (93ms)  : 92, 95
     .   : milestone, 93,
    master - mean (93ms)  : 92, 95
     .   : milestone, 93,

    section CallTarget+Inlining+NGEN
    This PR (7534) - mean (663ms)  : 648, 679
     .   : milestone, 663,
    master - mean (669ms)  : 656, 682
     .   : milestone, 669,

gantt
    title Execution time (ms) FakeDbCommand (.NET 8) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Bailout
    This PR (7534) - mean (93ms)  : 92, 94
     .   : milestone, 93,
    master - mean (93ms)  : 92, 94
     .   : milestone, 93,

    section Baseline
    This PR (7534) - mean (92ms)  : 89, 95
     .   : milestone, 92,
    master - mean (92ms)  : 90, 94
     .   : milestone, 92,

    section CallTarget+Inlining+NGEN
    This PR (7534) - mean (596ms)  : 580, 612
     .   : milestone, 596,
    master - mean (599ms)  : 586, 612
     .   : milestone, 599,

gantt
    title Execution time (ms) HttpMessageHandler (.NET Framework 4.8) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Bailout
    This PR (7534) - mean (195ms)  : 193, 198
     .   : milestone, 195,
    master - mean (195ms)  : 190, 200
     .   : milestone, 195,

    section Baseline
    This PR (7534) - mean (192ms)  : 188, 195
     .   : milestone, 192,
    master - mean (191ms)  : 186, 195
     .   : milestone, 191,

    section CallTarget+Inlining+NGEN
    This PR (7534) - mean (1,110ms)  : 1085, 1135
     .   : milestone, 1110,
    master - mean (1,104ms)  : 1071, 1138
     .   : milestone, 1104,

gantt
    title Execution time (ms) HttpMessageHandler (.NET Core 3.1) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Bailout
    This PR (7534) - mean (277ms)  : 273, 281
     .   : milestone, 277,
    master - mean (274ms)  : 269, 279
     .   : milestone, 274,

    section Baseline
    This PR (7534) - mean (275ms)  : 271, 279
     .   : milestone, 275,
    master - mean (272ms)  : 266, 279
     .   : milestone, 272,

    section CallTarget+Inlining+NGEN
    This PR (7534) - mean (901ms)  : 861, 940
     .   : milestone, 901,
    master - mean (893ms)  : 865, 921
     .   : milestone, 893,

gantt
    title Execution time (ms) HttpMessageHandler (.NET 6) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Bailout
    This PR (7534) - mean (269ms)  : 266, 272
     .   : milestone, 269,
    master - mean (266ms)  : 260, 272
     .   : milestone, 266,

    section Baseline
    This PR (7534) - mean (268ms)  : 264, 272
     .   : milestone, 268,
    master - mean (269ms)  : 263, 275
     .   : milestone, 269,

    section CallTarget+Inlining+NGEN
    This PR (7534) - mean (877ms)  : 846, 908
     .   : milestone, 877,
    master - mean (877ms)  : 846, 908
     .   : milestone, 877,

gantt
    title Execution time (ms) HttpMessageHandler (.NET 8) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Bailout
    This PR (7534) - mean (268ms)  : 263, 272
     .   : milestone, 268,
    master - mean (266ms)  : 260, 272
     .   : milestone, 266,

    section Baseline
    This PR (7534) - mean (268ms)  : 263, 272
     .   : milestone, 268,
    master - mean (266ms)  : 260, 272
     .   : milestone, 266,

    section CallTarget+Inlining+NGEN
    This PR (7534) - mean (789ms)  : 762, 815
     .   : milestone, 789,
    master - mean (785ms)  : 763, 807
     .   : milestone, 785,

andrewlock requested review from a team as code owners September 18, 2025 14:57

andrewlock added area:tracer The core tracer library (Datadog.Trace, does not include OpenTracing, native code, or integrations) area:profiler Issues related to the continous-profiler labels Sep 18, 2025

chatgpt-codex-connector Bot reviewed Sep 18, 2025

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Comment thread tracer/src/Datadog.Trace/ContinuousProfiler/ProfilerStatus.cs Outdated

andrewlock force-pushed the andrew/add-is-profiler-available-api branch 2 times, most recently from 0944855 to b17361c Compare September 18, 2025 15:17

chrisnas approved these changes Sep 18, 2025

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Comment thread tracer/src/Datadog.Trace/ContinuousProfiler/ProfilerStatus.cs Outdated

anna-git reviewed Sep 18, 2025

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andrewlock force-pushed the andrew/add-is-profiler-available-api branch from b17361c to 6ff0c01 Compare September 18, 2025 15:26

Add a profiler availability check

f717f50

andrewlock force-pushed the andrew/add-is-profiler-available-api branch from 6ff0c01 to f717f50 Compare September 18, 2025 15:42

Update tracer/src/Datadog.Trace/ContinuousProfiler/ProfilerStatus.cs

2ae3965

anna-git approved these changes Sep 18, 2025

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Add exclusion to config path

396f8bc

andrewlock enabled auto-merge (squash) September 19, 2025 08:34

andrewlock force-pushed the andrew/add-is-profiler-available-api branch 2 times, most recently from 638001b to a7efcbb Compare September 19, 2025 10:15

Refactor slightly for testing and add unit tests

1032927

andrewlock force-pushed the andrew/add-is-profiler-available-api branch from a7efcbb to 1032927 Compare September 19, 2025 11:41

andrewlock merged commit 6a6d4e9 into master Sep 19, 2025
155 of 158 checks passed

andrewlock deleted the andrew/add-is-profiler-available-api branch September 19, 2025 13:40

github-actions Bot added this to the vNext-v3 milestone Sep 19, 2025

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Add a Continuous Profiler availability check#7534

Add a Continuous Profiler availability check#7534
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andrewlock commented Sep 18, 2025

Summary of changes

Reason for change

Implementation details

Test coverage

Other details

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Execution-Time Benchmarks Report ⏱️

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