Add srv_src field to client stats payload by NachoEchevarria · Pull Request #8339 · DataDog/dd-trace-dotnet

NachoEchevarria · 2026-03-19T12:24:07Z

Summary of changes

Add srv_src field to the client stats payload, propagating the service name source alongside trace stats.

Reason for change

Per the service name source RFC, the source must be propagated in both trace and stats payloads. The trace payload (_dd.svc_src span meta) was added in PR #8302. This completes the implementation by adding srv_src at the stats bucket level.

Implementation details

StatsAggregationKey.cs: Added ServiceSource field. It participates in equality and hash code, so stats with different sources aggregate into distinct buckets.
StatsAggregator.cs: BuildKey() now reads span.Context.ServiceNameSource and passes it to the aggregation key.
StatsBuffer.cs: SerializeBucket() conditionally serializes srv_src when ServiceSource is non-null (dynamic map size: 13 with source, 12 without).

Test coverage

KeyEquality_WithServiceSource: Verifies that keys with different sources are not equal.
Serialization_WithServiceSource: Verifies srv_src is serialized when present and absent when null.
Existing StatsBufferTests and StatsAggregatorTests updated and passing.

Other details

APMLP-1015

Related agent PR: DataDog/datadog-agent#45982
Reference Java implementation: DataDog/dd-trace-java#10653

pr-commenter · 2026-03-19T13:05:28Z

Benchmarks

Benchmark execution time: 2026-03-27 17:20:18

Comparing candidate commit ab85a20 in PR branch nacho/ServiceSourceStats with baseline commit 017e910 in branch master.

Found 1 performance improvements and 8 performance regressions! Performance is the same for 264 metrics, 15 unstable metrics.

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 ----------------------------------'

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

🟥 execution_time [+77.269ms; +77.423ms] or [+60.816%; +60.937%]

scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.ObjectExtractorSimpleBody net6.0

🟥 execution_time [+11.335ms; +17.883ms] or [+5.657%; +8.925%]

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

🟥 execution_time [+24.996ms; +28.971ms] or [+14.064%; +16.301%]

scenario:Benchmarks.Trace.CIVisibilityProtocolWriterBenchmark.WriteAndFlushEnrichedTraces netcoreapp3.1

🟥 execution_time [+14.087ms; +21.474ms] or [+9.154%; +13.955%]
🟥 throughput [-186.445op/s; -132.633op/s] or [-11.954%; -8.504%]

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

🟥 allocated_mem [+19.932KB; +19.976KB] or [+7.721%; +7.738%]

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

🟩 throughput [+14850769.141op/s; +16106974.803op/s] or [+6.585%; +7.142%]

scenario:Benchmarks.Trace.SpanBenchmark.StartFinishScope net6.0

🟥 execution_time [+12.276ms; +15.614ms] or [+6.162%; +7.838%]

scenario:Benchmarks.Trace.SpanBenchmark.StartFinishScope netcoreapp3.1

🟥 execution_time [+16.156ms; +21.618ms] or [+8.177%; +10.942%]

dd-trace-dotnet-ci-bot · 2026-03-19T13:22:51Z

Execution-Time Benchmarks Report ⏱️

Execution-time results for samples comparing This PR (8339) and master.

⚠️ Potential regressions detected

HttpMessageHandler

Metric	Master (Mean ± 95% CI)	Current (Mean ± 95% CI)	Change	Status
.NET Framework 4.8 - Baseline
duration	193.46 ± (193.25 - 194.07) ms	220.36 ± (219.82 - 221.33) ms	+13.9%	❌⬆️
.NET Framework 4.8 - Bailout
duration	196.16 ± (196.05 - 196.84) ms	232.81 ± (232.17 - 234.83) ms	+18.7%	❌⬆️
.NET Framework 4.8 - CallTarget+Inlining+NGEN
duration	1150.65 ± (1151.26 - 1157.73) ms	1263.45 ± (1263.90 - 1273.02) ms	+9.8%	❌⬆️

Full Metrics Comparison

FakeDbCommand

Metric	Master (Mean ± 95% CI)	Current (Mean ± 95% CI)	Change	Status
.NET Framework 4.8 - Baseline
duration	72.15 ± (72.15 - 72.46) ms	71.82 ± (71.86 - 72.21) ms	-0.5%	✅
.NET Framework 4.8 - Bailout
duration	76.39 ± (76.17 - 76.50) ms	76.51 ± (76.26 - 76.60) ms	+0.2%	✅⬆️
.NET Framework 4.8 - CallTarget+Inlining+NGEN
duration	1073.18 ± (1072.51 - 1078.17) ms	1077.76 ± (1077.77 - 1085.43) ms	+0.4%	✅⬆️
.NET Core 3.1 - Baseline
process.internal_duration_ms	22.40 ± (22.35 - 22.45) ms	22.29 ± (22.26 - 22.33) ms	-0.5%	✅
process.time_to_main_ms	83.68 ± (83.44 - 83.92) ms	83.17 ± (82.97 - 83.36) ms	-0.6%	✅
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	10.91 ± (10.91 - 10.91) MB	10.92 ± (10.91 - 10.92) MB	+0.1%	✅⬆️
runtime.dotnet.threads.count	12 ± (12 - 12)	12 ± (12 - 12)	+0.0%	✅
.NET Core 3.1 - Bailout
process.internal_duration_ms	22.25 ± (22.21 - 22.29) ms	22.32 ± (22.29 - 22.36) ms	+0.3%	✅⬆️
process.time_to_main_ms	84.98 ± (84.78 - 85.18) ms	85.18 ± (84.96 - 85.40) ms	+0.2%	✅⬆️
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	10.94 ± (10.94 - 10.95) MB	10.95 ± (10.95 - 10.96) MB	+0.1%	✅⬆️
runtime.dotnet.threads.count	13 ± (13 - 13)	13 ± (13 - 13)	+0.0%	✅
.NET Core 3.1 - CallTarget+Inlining+NGEN
process.internal_duration_ms	223.85 ± (222.81 - 224.88) ms	222.19 ± (221.08 - 223.30) ms	-0.7%	✅
process.time_to_main_ms	533.57 ± (532.31 - 534.83) ms	533.84 ± (532.68 - 535.00) ms	+0.1%	✅⬆️
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	48.32 ± (48.29 - 48.35) MB	48.25 ± (48.22 - 48.28) MB	-0.1%	✅
runtime.dotnet.threads.count	28 ± (28 - 28)	28 ± (28 - 28)	-1.1%	✅
.NET 6 - Baseline
process.internal_duration_ms	21.00 ± (20.97 - 21.02) ms	20.99 ± (20.96 - 21.02) ms	-0.0%	✅
process.time_to_main_ms	72.14 ± (71.99 - 72.29) ms	72.06 ± (71.91 - 72.21) ms	-0.1%	✅
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	10.63 ± (10.63 - 10.63) MB	10.64 ± (10.63 - 10.64) MB	+0.1%	✅⬆️
runtime.dotnet.threads.count	10 ± (10 - 10)	10 ± (10 - 10)	+0.0%	✅
.NET 6 - Bailout
process.internal_duration_ms	21.02 ± (20.99 - 21.06) ms	20.85 ± (20.81 - 20.89) ms	-0.8%	✅
process.time_to_main_ms	73.19 ± (73.01 - 73.37) ms	72.80 ± (72.64 - 72.97) ms	-0.5%	✅
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	10.73 ± (10.73 - 10.73) MB	10.75 ± (10.75 - 10.75) MB	+0.2%	✅⬆️
runtime.dotnet.threads.count	11 ± (11 - 11)	11 ± (11 - 11)	+0.0%	✅
.NET 6 - CallTarget+Inlining+NGEN
process.internal_duration_ms	216.01 ± (214.61 - 217.40) ms	387.14 ± (384.80 - 389.48) ms	+79.2%	✅⬆️
process.time_to_main_ms	530.99 ± (529.64 - 532.35) ms	531.85 ± (530.91 - 532.79) ms	+0.2%	✅⬆️
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	50.12 ± (50.10 - 50.15) MB	50.36 ± (50.33 - 50.38) MB	+0.5%	✅⬆️
runtime.dotnet.threads.count	29 ± (29 - 29)	28 ± (28 - 28)	-1.3%	✅
.NET 8 - Baseline
process.internal_duration_ms	19.14 ± (19.09 - 19.18) ms	19.35 ± (19.31 - 19.38) ms	+1.1%	✅⬆️
process.time_to_main_ms	71.36 ± (71.18 - 71.54) ms	71.97 ± (71.81 - 72.13) ms	+0.9%	✅⬆️
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	7.69 ± (7.68 - 7.70) MB	7.68 ± (7.68 - 7.69) MB	-0.1%	✅
runtime.dotnet.threads.count	10 ± (10 - 10)	10 ± (10 - 10)	+0.0%	✅
.NET 8 - Bailout
process.internal_duration_ms	19.35 ± (19.31 - 19.38) ms	19.13 ± (19.10 - 19.17) ms	-1.1%	✅
process.time_to_main_ms	73.21 ± (73.05 - 73.37) ms	72.31 ± (72.17 - 72.45) ms	-1.2%	✅
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	7.75 ± (7.74 - 7.76) MB	7.73 ± (7.72 - 7.73) MB	-0.3%	✅
runtime.dotnet.threads.count	11 ± (11 - 11)	11 ± (11 - 11)	+0.0%	✅
.NET 8 - CallTarget+Inlining+NGEN
process.internal_duration_ms	160.07 ± (159.25 - 160.89) ms	308.18 ± (305.85 - 310.50) ms	+92.5%	✅⬆️
process.time_to_main_ms	490.08 ± (489.03 - 491.13) ms	490.98 ± (490.08 - 491.89) ms	+0.2%	✅⬆️
runtime.dotnet.exceptions.count	0 ± (0 - 0)	0 ± (0 - 0)	+0.0%	✅
runtime.dotnet.mem.committed	36.93 ± (36.90 - 36.95) MB	37.25 ± (37.23 - 37.27) MB	+0.9%	✅⬆️
runtime.dotnet.threads.count	28 ± (28 - 28)	27 ± (27 - 27)	-1.6%	✅

HttpMessageHandler

Metric	Master (Mean ± 95% CI)	Current (Mean ± 95% CI)	Change	Status
.NET Framework 4.8 - Baseline
duration	193.46 ± (193.25 - 194.07) ms	220.36 ± (219.82 - 221.33) ms	+13.9%	❌⬆️
.NET Framework 4.8 - Bailout
duration	196.16 ± (196.05 - 196.84) ms	232.81 ± (232.17 - 234.83) ms	+18.7%	❌⬆️
.NET Framework 4.8 - CallTarget+Inlining+NGEN
duration	1150.65 ± (1151.26 - 1157.73) ms	1263.45 ± (1263.90 - 1273.02) ms	+9.8%	❌⬆️
.NET Core 3.1 - Baseline
process.internal_duration_ms	187.25 ± (186.89 - 187.62) ms	213.03 ± (212.41 - 213.65) ms	+13.8%	✅⬆️
process.time_to_main_ms	80.70 ± (80.47 - 80.93) ms	91.28 ± (91.06 - 91.50) ms	+13.1%	✅⬆️
runtime.dotnet.exceptions.count	3 ± (3 - 3)	3 ± (3 - 3)	+0.0%	✅
runtime.dotnet.mem.committed	16.14 ± (16.11 - 16.17) MB	15.83 ± (15.82 - 15.85) MB	-1.9%	✅
runtime.dotnet.threads.count	20 ± (19 - 20)	20 ± (20 - 20)	+1.9%	✅⬆️
.NET Core 3.1 - Bailout
process.internal_duration_ms	186.52 ± (186.21 - 186.82) ms	211.82 ± (211.16 - 212.47) ms	+13.6%	✅⬆️
process.time_to_main_ms	82.09 ± (81.94 - 82.24) ms	92.87 ± (92.60 - 93.13) ms	+13.1%	✅⬆️
runtime.dotnet.exceptions.count	3 ± (3 - 3)	3 ± (3 - 3)	+0.0%	✅
runtime.dotnet.mem.committed	16.15 ± (16.13 - 16.18) MB	15.91 ± (15.90 - 15.93) MB	-1.5%	✅
runtime.dotnet.threads.count	21 ± (20 - 21)	21 ± (21 - 21)	+1.9%	✅⬆️
.NET Core 3.1 - CallTarget+Inlining+NGEN
process.internal_duration_ms	395.92 ± (394.50 - 397.34) ms	425.33 ± (423.76 - 426.91) ms	+7.4%	✅⬆️
process.time_to_main_ms	522.87 ± (521.84 - 523.90) ms	572.37 ± (571.09 - 573.66) ms	+9.5%	✅⬆️
runtime.dotnet.exceptions.count	3 ± (3 - 3)	3 ± (3 - 3)	+0.0%	✅
runtime.dotnet.mem.committed	58.82 ± (58.67 - 58.98) MB	59.16 ± (59.11 - 59.21) MB	+0.6%	✅⬆️
runtime.dotnet.threads.count	30 ± (30 - 30)	30 ± (30 - 30)	+0.5%	✅⬆️
.NET 6 - Baseline
process.internal_duration_ms	191.61 ± (191.24 - 191.97) ms	219.07 ± (218.44 - 219.71) ms	+14.3%	✅⬆️
process.time_to_main_ms	69.75 ± (69.61 - 69.89) ms	79.87 ± (79.66 - 80.09) ms	+14.5%	✅⬆️
runtime.dotnet.exceptions.count	4 ± (4 - 4)	4 ± (4 - 4)	+0.0%	✅
runtime.dotnet.mem.committed	16.12 ± (15.98 - 16.25) MB	16.15 ± (16.13 - 16.17) MB	+0.2%	✅⬆️
runtime.dotnet.threads.count	19 ± (18 - 19)	20 ± (20 - 20)	+4.9%	✅⬆️
.NET 6 - Bailout
process.internal_duration_ms	191.37 ± (190.95 - 191.78) ms	218.06 ± (217.44 - 218.67) ms	+13.9%	✅⬆️
process.time_to_main_ms	71.00 ± (70.85 - 71.16) ms	80.99 ± (80.80 - 81.18) ms	+14.1%	✅⬆️
runtime.dotnet.exceptions.count	4 ± (4 - 4)	4 ± (4 - 4)	+0.0%	✅
runtime.dotnet.mem.committed	16.07 ± (15.92 - 16.22) MB	16.20 ± (16.19 - 16.22) MB	+0.8%	✅⬆️
runtime.dotnet.threads.count	20 ± (20 - 20)	21 ± (20 - 21)	+4.1%	✅⬆️
.NET 6 - CallTarget+Inlining+NGEN
process.internal_duration_ms	413.66 ± (412.25 - 415.07) ms	600.34 ± (597.36 - 603.32) ms	+45.1%	✅⬆️
process.time_to_main_ms	523.82 ± (522.76 - 524.87) ms	574.67 ± (573.35 - 575.99) ms	+9.7%	✅⬆️
runtime.dotnet.exceptions.count	4 ± (4 - 4)	4 ± (4 - 4)	+0.0%	✅
runtime.dotnet.mem.committed	60.94 ± (60.90 - 60.99) MB	61.72 ± (61.63 - 61.81) MB	+1.3%	✅⬆️
runtime.dotnet.threads.count	31 ± (30 - 31)	31 ± (31 - 31)	+1.1%	✅⬆️
.NET 8 - Baseline
process.internal_duration_ms	188.84 ± (188.46 - 189.21) ms	214.99 ± (214.38 - 215.59) ms	+13.8%	✅⬆️
process.time_to_main_ms	69.45 ± (69.24 - 69.65) ms	78.23 ± (78.03 - 78.42) ms	+12.6%	✅⬆️
runtime.dotnet.exceptions.count	4 ± (4 - 4)	4 ± (4 - 4)	+0.0%	✅
runtime.dotnet.mem.committed	11.79 ± (11.77 - 11.82) MB	11.51 ± (11.49 - 11.52) MB	-2.4%	✅
runtime.dotnet.threads.count	18 ± (18 - 18)	19 ± (19 - 19)	+4.3%	✅⬆️
.NET 8 - Bailout
process.internal_duration_ms	188.15 ± (187.87 - 188.42) ms	213.99 ± (213.42 - 214.56) ms	+13.7%	✅⬆️
process.time_to_main_ms	70.31 ± (70.19 - 70.44) ms	79.42 ± (79.24 - 79.60) ms	+13.0%	✅⬆️
runtime.dotnet.exceptions.count	4 ± (4 - 4)	4 ± (4 - 4)	+0.0%	✅
runtime.dotnet.mem.committed	11.80 ± (11.73 - 11.86) MB	11.56 ± (11.54 - 11.57) MB	-2.0%	✅
runtime.dotnet.threads.count	19 ± (19 - 19)	20 ± (20 - 20)	+5.0%	✅⬆️
.NET 8 - CallTarget+Inlining+NGEN
process.internal_duration_ms	340.99 ± (339.88 - 342.11) ms	609.73 ± (603.75 - 615.72) ms	+78.8%	✅⬆️
process.time_to_main_ms	480.85 ± (479.91 - 481.79) ms	531.86 ± (530.90 - 532.82) ms	+10.6%	✅⬆️
runtime.dotnet.exceptions.count	4 ± (4 - 4)	4 ± (4 - 4)	+0.0%	✅
runtime.dotnet.mem.committed	48.81 ± (48.77 - 48.85) MB	51.83 ± (51.75 - 51.91) MB	+6.2%	✅⬆️
runtime.dotnet.threads.count	30 ± (30 - 30)	30 ± (30 - 30)	+0.1%	✅⬆️

Comparison explanation

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 highlighted 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).

Duration charts

FakeDbCommand (.NET Framework 4.8)

gantt
    title Execution time (ms) FakeDbCommand (.NET Framework 4.8)
    dateFormat  x
    axisFormat %Q
    todayMarker off
    section Baseline
    This PR (8339) - mean (72ms)  : 69, 75
    master - mean (72ms)  : 70, 75

    section Bailout
    This PR (8339) - mean (76ms)  : 75, 78
    master - mean (76ms)  : 75, 78

    section CallTarget+Inlining+NGEN
    This PR (8339) - mean (1,082ms)  : 1027, 1136
    master - mean (1,075ms)  : 1035, 1115

FakeDbCommand (.NET Core 3.1)

gantt
    title Execution time (ms) FakeDbCommand (.NET Core 3.1)
    dateFormat  x
    axisFormat %Q
    todayMarker off
    section Baseline
    This PR (8339) - mean (112ms)  : 109, 116
    master - mean (113ms)  : 107, 119

    section Bailout
    This PR (8339) - mean (114ms)  : 112, 117
    master - mean (114ms)  : 111, 117

    section CallTarget+Inlining+NGEN
    This PR (8339) - mean (795ms)  : 768, 822
    master - mean (796ms)  : 773, 818

FakeDbCommand (.NET 6)

gantt
    title Execution time (ms) FakeDbCommand (.NET 6)
    dateFormat  x
    axisFormat %Q
    todayMarker off
    section Baseline
    This PR (8339) - mean (99ms)  : 96, 103
    master - mean (99ms)  : 96, 103

    section Bailout
    This PR (8339) - mean (100ms)  : 97, 103
    master - mean (100ms)  : 97, 103

    section CallTarget+Inlining+NGEN
    This PR (8339) - mean (947ms)  : crit, 914, 980
    master - mean (782ms)  : 758, 807

FakeDbCommand (.NET 8)

gantt
    title Execution time (ms) FakeDbCommand (.NET 8)
    dateFormat  x
    axisFormat %Q
    todayMarker off
    section Baseline
    This PR (8339) - mean (99ms)  : 96, 102
    master - mean (98ms)  : 95, 101

    section Bailout
    This PR (8339) - mean (99ms)  : 96, 102
    master - mean (100ms)  : 98, 103

    section CallTarget+Inlining+NGEN
    This PR (8339) - mean (830ms)  : crit, 795, 865
    master - mean (689ms)  : 668, 710

HttpMessageHandler (.NET Framework 4.8)

gantt
    title Execution time (ms) HttpMessageHandler (.NET Framework 4.8)
    dateFormat  x
    axisFormat %Q
    todayMarker off
    section Baseline
    This PR (8339) - mean (221ms)  : 209, 232
    master - mean (194ms)  : 189, 198

    section Bailout
    This PR (8339) - mean (234ms)  : crit, 214, 253
    master - mean (196ms)  : 193, 200

    section CallTarget+Inlining+NGEN
    This PR (8339) - mean (1,268ms)  : crit, 1198, 1339
    master - mean (1,154ms)  : 1108, 1201

HttpMessageHandler (.NET Core 3.1)

gantt
    title Execution time (ms) HttpMessageHandler (.NET Core 3.1)
    dateFormat  x
    axisFormat %Q
    todayMarker off
    section Baseline
    This PR (8339) - mean (315ms)  : 304, 325
    master - mean (276ms)  : 270, 283

    section Bailout
    This PR (8339) - mean (314ms)  : crit, 302, 326
    master - mean (277ms)  : 273, 281

    section CallTarget+Inlining+NGEN
    This PR (8339) - mean (1,040ms)  : crit, 1006, 1073
    master - mean (950ms)  : 921, 979

HttpMessageHandler (.NET 6)

gantt
    title Execution time (ms) HttpMessageHandler (.NET 6)
    dateFormat  x
    axisFormat %Q
    todayMarker off
    section Baseline
    This PR (8339) - mean (308ms)  : 294, 322
    master - mean (269ms)  : 264, 274

    section Bailout
    This PR (8339) - mean (308ms)  : crit, 297, 319
    master - mean (270ms)  : 265, 276

    section CallTarget+Inlining+NGEN
    This PR (8339) - mean (1,207ms)  : crit, 1156, 1258
    master - mean (968ms)  : 945, 991

HttpMessageHandler (.NET 8)

gantt
    title Execution time (ms) HttpMessageHandler (.NET 8)
    dateFormat  x
    axisFormat %Q
    todayMarker off
    section Baseline
    This PR (8339) - mean (304ms)  : 292, 316
    master - mean (268ms)  : 262, 274

    section Bailout
    This PR (8339) - mean (304ms)  : crit, 294, 314
    master - mean (268ms)  : 264, 272

    section CallTarget+Inlining+NGEN
    This PR (8339) - mean (1,172ms)  : crit, 1082, 1263
    master - mean (852ms)  : 833, 871

andrewlock

As discussed, we're missing a lot from the spec, but hey 🤷‍♂️

andrewlock · 2026-03-20T12:16:46Z

tracer/src/Datadog.Trace/Agent/StatsBuffer.cs


+            if (hasServiceSource)
+            {
+                MessagePackBinary.WriteString(stream, "srv_src");


Based on the stats computation spec, I think this should be service_source, but given that none of our keys match here, I don't know what's correct 😅

Suggested change

MessagePackBinary.WriteString(stream, "srv_src");

MessagePackBinary.WriteString(stream, "service_source");

We should wait for clarification. Thanks for finding that!

Does this need to be service_source?

No, its srv_src. We had a discussion. Also, the system tests PR confirms the field name: DataDog/system-tests#6565

The spec Andrew posted above needs to be updated?

Yes, it does, but they are already notified.

andrewlock · 2026-03-20T12:16:52Z

tracer/test/Datadog.Trace.TestHelpers/Stats/MockClientGroupedStats.cs

    [Key("TopLevelHits")]
    public long TopLevelHits { get; set; }
+
+    [Key("srv_src")]


Suggested change

[Key("srv_src")]

[Key("service_source")]

NachoEchevarria · 2026-03-27T09:10:19Z

Note: System test was tested manually by chaging temprarily the pipeline: https://github.com/DataDog/system-tests/pull/6598/changes

bouwkast

LGTM

The service_source vs svc_src question doesn't look answered yet which seems to be the only concern

bouwkast · 2026-03-27T13:10:09Z

tracer/src/Datadog.Trace/Agent/StatsBuffer.cs


+            if (hasServiceSource)
+            {
+                MessagePackBinary.WriteString(stream, "srv_src");


Does this need to be service_source?

lucaspimentel · 2026-03-27T13:34:00Z

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chatgpt-codex-connector · 2026-03-27T13:39:12Z

tracer/src/Datadog.Trace/Agent/StatsAggregator.cs

                span.ServiceName,
                span.OperationName,
                span.Type,
+                span.Context.ServiceNameSource,


Normalize service source before adding it to stats key

Use of span.Context.ServiceNameSource here bypasses the safety normalization used for trace serialization: when a span’s service equals the default service, non-opt.* sources are intentionally cleared before _dd.svc_src is emitted. In this path, those sources are still preserved, so spans can produce stats buckets with srv_src (and separate aggregation keys) even when the corresponding trace payload drops the source. A concrete case is setting ISpan.ServiceName to the default service, which sets source m; this now creates inconsistent trace-vs-stats attribution and extra timeseries cardinality.

Useful? React with 👍 / 👎.

setting ISpan.ServiceName to the default service, which sets source m

That's a good question. Should this be considered "manual" or "default"? (in both the _dd.svc_src tag and the trace stats)

Yes, we should apply the same logic for that corner case. If user sets the service name to Default, no tags or stats should be emitted. Fixed.

NachoEchevarria · 2026-03-27T13:39:19Z

LGTM

The service_source vs svc_src question doesn't look answered yet which seems to be the only concern

We had a discussion regarding the topic and the right name is srv_src. Also, the system tests PR confirms the field name: DataDog/system-tests#6565

lucaspimentel · 2026-03-27T13:43:38Z

tracer/src/Datadog.Trace/Agent/StatsAggregationKey.cs

        public readonly string Service;
        public readonly string OperationName;
        public readonly string Type;
+        public readonly string ServiceSource;


Not a blocker, but maybe add #nullable enabled while you're here and declare some of these as string?? 😅

That's a good point. I can do that in a subsequent PR. We would need to check what fields can be null and check the callers. It's worth to do that, but probably in a new PR. Also, using scoped namespaces. I promise I will create a subsequent PR. :)

That's a good point. I can do that in a subsequent PR

Please don't, it'll conflict with mine 😄

NachoEchevarria added 27 commits March 19, 2026 13:16

initial implementation

e7ea99d

update snapshots

43c805c

update snapshots

45a3914

fix duplicated

fa1e92c

Avoid two calls to GetServiceName

dfd5800

Add warning comments for enum sync

891cd46

rename param

92b5de7

Remove not needed

9495c55

Remove not needed

1603764

Refactor: Use ServiceNameMetadata to decrease double method calls.

83c03be

Fix unit tests

fb7e24a

remove integration arrays

b487692

Refactor schemas

76423c9

Use opt.service_mapping even if default

2e0044c

Fix dbscopefactory

d76c65e

Final check serviceNameEqualsDefault

6ef7bb5

SpanMessagePackFormatter opt case

18105ba

Add unit tests

42401b0

Minor refactor

564ff19

remove hardcoded

19abb0a

Initial implementation

3df9559

Fix unit. Azure Aws add source.

571a6e8

fix unit tests and integration tests

cbf0b86

Update v1 rules

02ecf55

Update OTEL

1721030

Remove commas

5bc3666

serivoce source stats. Initial implementation.

337c5fe

NachoEchevarria added the area:tracer The core tracer library (Datadog.Trace, does not include OpenTracing, native code, or integrations) label Mar 19, 2026

NachoEchevarria changed the title ~~Nacho/service source stats~~ Add srv_src field to client stats payload Mar 19, 2026

NachoEchevarria and others added 2 commits March 20, 2026 11:14

protect against empty strings

c80fcaf

Merge branch 'master' into nacho/ServiceSourceStats

d6e12c2

NachoEchevarria marked this pull request as ready for review March 20, 2026 11:34

NachoEchevarria requested a review from a team as a code owner March 20, 2026 11:34

andrewlock approved these changes Mar 20, 2026

View reviewed changes

Temporary change to test the stat system test

a0ae1f7

NachoEchevarria requested a review from a team as a code owner March 26, 2026 10:52

NachoEchevarria and others added 3 commits March 26, 2026 14:19

Merge branch 'master' into nacho/ServiceSourceStats

9fd8d2e

Fix compilation errors from merge.

6415ecb

Undo temporary changes.

2afede6

bouwkast approved these changes Mar 27, 2026

View reviewed changes

chatgpt-codex-connector bot reviewed Mar 27, 2026

View reviewed changes

lucaspimentel reviewed Mar 27, 2026

View reviewed changes

Apply default name logic in stats

4575bcd

lucaspimentel approved these changes Mar 27, 2026

View reviewed changes

get default service name from span

ab85a20

	MessagePackBinary.WriteString(stream, "srv_src");
	MessagePackBinary.WriteString(stream, "service_source");

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

scenario:Benchmarks.Trace.Asm.AppSecBodyBenchmark.ObjectExtractorSimpleBody net6.0

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

scenario:Benchmarks.Trace.CIVisibilityProtocolWriterBenchmark.WriteAndFlushEnrichedTraces netcoreapp3.1

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

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

scenario:Benchmarks.Trace.SpanBenchmark.StartFinishScope net6.0

scenario:Benchmarks.Trace.SpanBenchmark.StartFinishScope netcoreapp3.1

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HttpMessageHandler

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HttpMessageHandler

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