Use low precision Clock#now when computing timestamp for exemplars#6417
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jack-berg merged 3 commits intoopen-telemetry:mainfrom May 1, 2024
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Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## main #6417 +/- ##
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- Coverage 91.12% 91.11% -0.01%
- Complexity 5856 5868 +12
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Files 636 636
Lines 17062 17082 +20
Branches 1733 1741 +8
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+ Hits 15548 15565 +17
- Misses 1019 1021 +2
- Partials 495 496 +1 ☔ View full report in Codecov by Sentry. |
trask
approved these changes
May 1, 2024
| this.attributes = attributes; | ||
| // Note: It may make sense in the future to attempt to pull this from an active span. | ||
| this.recordTime = clock.now(); | ||
| // High precision time is not worth the additional performance expense it incurs for exemplars |
Contributor
|
what JVM version were you using to benchmark with? (not that it matters much..but might be nice to include in the PR description for posterity). |
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Updated! |
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Resolves #6403.
Introduces a new
Clock#now(boolean highPrecision)overload, which uses a performance optimized millisecond precision whenhighPrecision=false. UpdatesReservoirCellto obtain measurement times usingClock#now(false), which shaves a good chunk of time off the time to record each exemplar (~50ns on my machine).This has a greater impact the more frequent measurements are candidates to be stored in ReservoirCell. The savings are especially impactful for the histogram exemplar reservoir, where the algorithm requires us to take the last measurement for each bucket. This means we compute the time for every measurement recorded.
Here's a benchmark output comparing the high precision and low precision
Clock#nowimplementations. Benchmark run usingOpenJDK Runtime Environment Temurin-17.0.3+7.